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Winter solstice
Winter solstice
Winter solstice
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Winter Solstice
Sunset at Stonehenge in England during the winter solstice in the Northern Hemisphere
Also calledMidwinter; the Shortest Day; the Longest Night
Observed byVarious cultures
TypeCultural, astronomical
SignificanceBeginning of lengthening days and shortening nights
CelebrationsFeasting
DateDecember 21 or December 22
(Northern Hemisphere)
and June 20 or June 21
(Southern Hemisphere)
Related toWinter festivals
A view of Earth on the Northern hemisphere's winter solstice, with the North pole tilted furthest away from the Sun

The winter solstice, or hibernal solstice, occurs when either of Earth's poles reaches its maximum tilt away from the Sun. This happens twice yearly, once in each hemisphere (Northern and Southern). For that hemisphere, the winter solstice is the day with the shortest period of daylight and longest night of the year, and when the Sun is at its lowest arc in the sky.[1] In each polar region, there is continuous darkness or twilight around its winter solstice. The opposite event is the summer solstice, which happens at the same time in the opposite hemisphere.

The winter solstice occurs during the hemisphere's winter. In the Northern Hemisphere, this is the December solstice (December 21 or 22) and in the Southern Hemisphere, this is the June solstice (June 20 or 21). Although the winter solstice itself lasts only a moment, the term also refers to the day on which it occurs. Traditionally, in many temperate regions, the winter solstice is seen as the middle of winter, and "midwinter" is another name for the winter solstice, although it carries other meanings as well. Other names are the "extreme of winter", the "shortest day" and the "longest night".

Since prehistory, the winter solstice has been a significant time of year in many cultures and has been marked by festivals and rites.[2] This is because it is the point when the shortening of daylight hours is reversed and the daytime begins to lengthen again. In parts of Europe it was seen as the symbolic death and rebirth of the Sun. Some ancient monuments such as Newgrange, Stonehenge, and Cahokia Woodhenge are aligned with the sunrise or sunset on the winter solstice.

History and cultural significance

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The winter solstice is the reversal of the Sun's apparent ebbing in the sky; the daytime stops becoming shorter and begins to lengthen again. In parts of ancient Europe, this was symbolized as the death and rebirth of the Sun, or of a Sun god.[3][4][5]

There is evidence that the winter solstice was deemed an important time of the yearly cycle for some cultures as far back as the Neolithic (New Stone Age). Astronomical events were often used to guide farming activities, such as the sowing of crops and mating of animals. Livestock were slaughtered so they would not have to be fed during the winter, so it was almost the only time of year when there was a plentiful supply of fresh meat for feasting.[6]

Neolithic Europe

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Sunlight entering the passage of Newgrange in Ireland on the winter solstice

Some important Neolithic and early Bronze Age archaeological sites in Europe are associated with the winter solstice, such as Stonehenge in England and Newgrange in Ireland (for others see List of archaeoastronomical sites by country). The primary axes of these two monuments seem to have been carefully aligned on a sight-line pointing to the winter solstice sunrise (Newgrange) and the winter solstice sunset (Stonehenge). Newgrange was built with a "light box" so that direct sunlight reaches the inner chamber only on the winter solstice.[7] At Stonehenge, the great trilithon, the Heel Stone and the avenue are aligned to the winter solstice sunset.[8] The Neolithic Goseck Circle in Germany has two openings, aligned with the winter solstice sunrise and sunset respectively.[7]

Ancient Egypt

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A 10th century BC papyrus showing Harpocrates (Horus the Child) inside a sun disk

Several ancient Egyptian temples are aligned with the winter solstice sunrise, including the Temple of Amun-Ra at Karnak, the chapel of Ra-Horakhty at Abu Simbel, and the Mortuary temple of Hatshepsut at Luxor.[9]

Plutarch wrote in the Moralia (first century AD) that the Egyptians believed the goddess Isis gave birth to Harpocrates (Horus the Child) at the winter solstice.[10] Macrobius wrote in the fourth century that the Sun appears small at the winter solstice, and on this shortest day, the Egyptians brought an idol of a child Sun god out of a shrine.[11] In his Panarion, also from the fourth century, Epiphanius of Salamis wrote that the winter solstice was celebrated on 25 December in Alexandria as the Kikellia. Epiphanius says that thirteen days after the solstice, on 5–6 January, they celebrated the birth of Aion, son of the virgin goddess Kore. At the temple of Kore (the Koreion) in Alexandria, an all-night vigil was held, and at dawn an idol of the child god was brought out of an underground shrine. This idol was carried around the temple seven times, accompanied by music, hymns and revelry.[12][13]

Ancient Roman world

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A 2nd–3rd century AD relief of Sol, whose birthday was the winter solstice

In the ancient Roman calendar, December 25 was the date of the winter solstice.[14][15] Marcus Terentius Varro wrote in the first century BC that this was regarded as the middle of winter.[16] In the same century, Ovid wrote in the Fasti that the winter solstice is the first day of the "new Sun".[17] The Calendar of Antiochus of Athens, c. second century AD, marks it as the "birthday of the Sun".[18] In AD 274, the emperor Aurelian made this the date of the festival Dies Natalis Solis Invicti, the birthday of Sol Invictus or the 'Invincible Sun'.[15][19] Gary Forsythe, Professor of Ancient History, says "This celebration would have formed a welcome addition to the seven-day period of the Saturnalia (December 17–23), Rome's most joyous holiday season since Republican times, characterized by parties, banquets, and exchanges of gifts".[15]

Liturgical historians generally accept that the winter solstice had some influence on the choice of December 25 as the date of Christmas.[20] A widely-held theory is that the Church chose it as Christ's birthday (Dies Natalis Christi) specifically to appropriate the Roman festival of the sun god's birthday (Dies Natalis Solis Invicti).[19][15][21] According to C. Philipp E. Nothaft, a professor at Trinity College Dublin, though this "is nowadays used as the default explanation for the choice of 25 December as Christ's birthday, few advocates of this theory seem to be aware of how paltry the available evidence actually is".[22]

Germanic

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Main article: Midwinter
Illustration of an Old Nordic Yule festival, from Die Gartenlaube, 1880

In the sixth century, the Greek historian Procopius wrote that the people of Scandinavia (which he calls Thule) held their greatest festival shortly after the winter solstice, to celebrate the return of daylight.[23]

In Anglo-Saxon England the winter solstice was generally deemed to be December 25, and in Old English, midwinter could mean both the winter solstice and Christmas.[24][25] In the eighth century, Bede wrote that the pagan Anglo-Saxons had celebrated the festival Mōdraniht ('Mothers' Night') at the winter solstice, which marked the start of the Anglo-Saxon year.[25]

Bede also wrote that the pagan Anglo-Saxons called both December and January Giuli. Bede links this term with the winter solstice, writing that "The months of Giuli derive their name from the day when the Sun turns back [and begins] to increase".[26] This is an Old English form of the word 'Yule', and it is also spelled Geōl, Geōla and Iūla. Other Old English writers call December Ǣrra Geōla (the former Yule) and January Æftera Geōla (the latter Yule).[27][28][29]

The North Germanic peoples celebrated a winter holiday called Jól, the Old Norse form of the word 'Yule'. The Heimskringla, written in the 13th century by the Icelander Snorri Sturluson, describes a Jól feast hosted by the Norwegian king Haakon the Good (c. 920–961). According to Snorri, the Christian Haakon had moved Jól from "midwinter" and aligned it with Christmas. This led some scholars to believe that Scandinavian Yule (Jól) originally was a sun festival on the winter solstice. Modern scholars generally do not believe this, as the medieval Icelandic "midwinter" (miðvetr) was about four weeks after the solstice.[30] During the Christianisation of the Germanic peoples, Yule was incorporated into the Christmas celebrations and the term and its cognates still refer to Christmas in modern Northern European languages such as Swedish.

Albanian

[edit]

Albanian traditional festivities around the winter solstice celebrate the return of the Sun (Dielli) for summer and the lengthening of the days.[31][32][33][34] The Albanian traditional rites during the winter solstice period are pagan, and very ancient. Albanologist Johann Georg von Hahn (1811 – 1869) reported that Christian clergy, during his time and before, have vigorously fought the pagan rites that were practiced by Albanians to celebrate this festivity, but without success.[35]

The old rites of this festivity were accompanied by collective fires (zjarre) based on the house, kinship or neighborhood, a practice performed in order to give strength to the Sun according to the old beliefs. The rites related to the cult of vegetation, which expressed the desire for increased production in agriculture and animal husbandry, were accompanied by animal sacrifices to the fire, lighting pine trees at night, luck divination tests with crackling in the fire or with coins in ritual bread, making and consuming ritual foods, performing various magical ritualistic actions in livestock, fields, vineyards and orchards, and so on.[35][36][37]

Nata e Buzmit, "Yule log's night", is celebrated between December 22 and January 6.[38] Buzmi is a ritualistic piece of wood (or several pieces of wood) that is put to burn in the fire (zjarri) of the hearth (vatër) on the night of a winter celebration that falls after the return of the Sun for summer (after the winter solstice), sometimes on the night of Kërshëndella on December 24 (Christmas Eve), sometimes on the night of kolendra, or sometimes on New Year's Day or on any other occasion around the same period, a tradition that is originally related to the cult of the Sun.[39][36][37]

East Asian

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Main article: Dongzhi Festival
Japanese Sun goddess Amaterasu emerging from a cave (by Kunisada)
Sunlight directed through the 17 arches of Seventeen Arch Bridge, Summer Palace, Beijing around winter solstice

In East Asia, the winter solstice has been celebrated as one of the Twenty-four Solar Terms, called Dongzhi (冬至) in Chinese. In Japan, in order not to catch cold in the winter, there is a custom to soak oneself in a yuzu hot bath (Japanese: 柚子湯 = Yuzuyu).[40]

Indian

[edit]
Main article: Makar Sankranti

Makara Sankranti, also known as Makara Sankrānti (Sanskrit: मकर संक्रांति) or Maghi, is a festival day in the Hindu calendar, in reference to deity Surya (sun). It is observed each year in January.[41] It marks the first day of Sun's transit into Makara (Capricorn), marking the end of the month with the winter solstice and the start of longer days.[41][42]

Iranian

[edit]
Main article: Yaldā Night

Iranian people celebrate the night of the Northern Hemisphere's winter solstice as, "Yalda night", which is known to be the "longest and darkest night of the year". Yalda night celebration, or as some call it "Shabe Chelleh" ("the 40th night"), is one of the oldest Iranian traditions that has been present in Persian culture from ancient times. In this night all the family gather together, usually at the house of the eldest, and celebrate it by eating, drinking and reciting poetry (esp. Hafez). Nuts, pomegranates and watermelons are particularly served during this festival.

Judaic

[edit]

An Aggadic legend found in tractate Avodah Zarah 8a puts forth the talmudic hypothesis that Adam first established the tradition of fasting before the winter solstice, and rejoicing afterward, which festival later developed into the Roman Saturnalia and Kalendae.

When the First Man saw that the day was continuously shortening, he said, "Woe is me! Because I have sinned, the world darkens around me, and returns to formlessless and void. This is the death to which Heaven has sentenced me!" He decided to spend eight days in fasting and prayer. When he saw the winter solstice, and he saw that the day was continuously lengthening, he said, "It is the order of the world!" He went and feasted for eight days. The following year, he feasted for both. He established them in Heaven's name, but they established them in the name of idolatry[43]

Observation

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Main article: Solstice § Solstice determination
UT date and time of equinoxes and solstices on Earth[44][45]
event equinox solstice equinox solstice
month March[46] June[47] September[48] December[49]
year day time day time day time day time
2021 20 09:37 21 03:32 22 19:21 21 15:59
2022 20 15:33 21 09:14 23 01:04 21 21:48
2023 20 21:25 21 14:58 23 06:50 22 03:28
2024 20 03:07 20 20:51 22 12:44 21 09:20
2025 20 09:01 21 02:42 22 18:19 21 15:03
2026 20 14:46 21 08:25 23 00:06 21 20:50
2027 20 20:25 21 14:11 23 06:02 22 02:43
2028 20 02:17 20 20:02 22 11:45 21 08:20
2029 20 08:01 21 01:48 22 17:37 21 14:14
2030 20 13:51 21 07:31 22 23:27 21 20:09
2031 20 19:41 21 13:17 23 05:15 22 01:56

Although the instant of the solstice can be calculated,[50] direct observation of the moment by visual perception is elusive. The Sun moves too slowly or appears to stand still (the meaning of "solstice"). However, by use of astronomical data tracking, the precise timing of its occurrence is now public knowledge. The precise instant of the solstice cannot be directly detected (by definition, people cannot observe that an object has stopped moving until it is later observed that it has not moved further from the preceding spot, or that it has moved in the opposite direction).[citation needed] To be precise to a single day, observers must be able to view a change in azimuth or elevation less than or equal to about 1/60 of the angular diameter of the Sun. Observing that it occurred within a two-day period is easier, requiring an observation precision of only about 1/16 of the angular diameter of the Sun. Thus, many observations are of the day of the solstice rather than the instant. This is often done by observing sunrise and sunset or using an astronomically aligned instrument that allows a ray of light to be cast on a certain point around that time. The earliest sunset and latest sunrise dates differ from winter solstice, however, and these depend on latitude, due to the variation in the solar day throughout the year caused by the Earth's elliptical orbit (see earliest and latest sunrise and sunset).

List of winter solstice festivals and observances

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See also

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References

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Further reading

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Revisions and contributorsEdit on WikipediaRead on Wikipedia

Winter solstice

View on Grokipedia
from Grokipedia
The winter solstice is an annual astronomical event that marks the astronomical beginning of winter in the , featuring the shortest day and longest night of the year as the Earth's tilts farthest away from the Sun. This positioning causes the Sun to reach its southernmost , appearing directly overhead the at 23.5° south latitude, resulting in the least amount of daylight for locations north of the . The phenomenon stems from Earth's of approximately 23.5 degrees relative to its around the Sun, which creates the seasonal variations in sunlight distribution. In the , the same event signifies , bringing the longest day and shortest night. Historically, the winter solstice has been observed and celebrated by diverse cultures worldwide as a pivotal moment of renewal and the return of light after the darkest night. Ancient monuments, such as in , align with the solstice sunset along its primary axis, suggesting prehistoric communities used the site for astronomical observations and rituals tied to the Sun's cycle. In , Native American groups at sites like constructed temple pyramids oriented to capture the solstice sunrise, integrating celestial events into their spiritual and communal practices. Similarly, Spanish colonial missions in feature designs where a solstice illuminates sacred objects, blending indigenous astronomical knowledge with Christian symbolism. One prominent modern tradition is Iran's Yalda festival, rooted in ancient Persian beliefs, where families gather through the longest night to share fruits like pomegranates and recite , symbolizing the victory of light and goodness over darkness and evil. These observances underscore the solstice's enduring role in fostering , reflection, and hope across hemispheres and eras.

Astronomical foundations

Definition and occurrence

The winter solstice is the instant when the Sun reaches its southernmost point in the sky, marking the shortest day of the year in the Northern Hemisphere due to the Earth's positioning the at its maximum distance from the Sun, resulting in the longest night of the year. In the , this same event, known as the , instead produces the longest day and shortest night, as the is tilted toward the Sun. This positioning occurs due to the planet's 23.44-degree axial obliquity, which causes uneven distribution of sunlight across the hemispheres. The winter solstice in the typically occurs around December 21, though the exact date varies slightly each year—falling between December 20 and 23—owing to the dynamics of Earth's elliptical orbit and alignments. Conversely, the experiences its winter solstice around June 21, with similar minor annual variations between June 20 and 22. These timings reflect the solstice's role as a pivotal point in Earth's annual journey around the Sun, opposite the summer solstice, together delineating the extremes of seasonal daylight cycles. The term "solstice" derives from the Latin solstitium, combining sol ("sun") and sistere ("to stand still"), describing the apparent cessation of the Sun's northward or southward movement along the as observed from . This nomenclature captures the phenomenon where, at the solstice, the Sun reaches its farthest from the , appearing to pause in its path before reversing direction.

Cause and solar geometry

The winter solstice arises primarily from 's axial , or obliquity, of approximately 23.44 degrees relative to the plane of its orbit around the Sun. This fixed tilt causes the planet's hemispheres to alternately face toward or away from the Sun as completes its annual orbit, resulting in seasonal variations in sunlight distribution. Without this tilt, sunlight would strike more uniformly year-round, eliminating the solstices and equinoxes. At the December solstice, the reaches its maximum tilt away from the Sun, positioning the in near-total darkness for months in polar regions while the and receive more direct rays. This orientation minimizes the angle of incoming solar radiation in the north, spreading sunlight over a larger surface area and shortening daylight hours, which contributes to cooler temperatures and winter conditions. In contrast, the experiences its analog at this time, with the tilted toward the Sun. From an astronomical perspective, the Sun achieves its southernmost declination of about -23.44 degrees on the —an imaginary dome centered on used to map stellar positions—marking the winter solstice for northern observers. measures the Sun's angular distance north or south of the , analogous to on . The Sun follows the , the apparent annual path tracing 's orbital plane projected onto the , inclined at 23.44 degrees to the . At the solstice, the Sun's position along the aligns such that it appears directly overhead at the (23.44° S ), the southernmost parallel where this occurs. The name "solstice," from the Latin solstitium meaning "sun stands still," reflects the Sun's apparent pause at this extreme before its daily north-south path reverses direction over subsequent days.

Date variations by hemisphere and calendar

The winter solstice occurs at opposite times in the two hemispheres due to Earth's and orbital position around the Sun. In the , it typically falls between December 20 and 23, marking the shortest day of the year as the is tilted farthest from the Sun. Conversely, in the , the winter solstice happens between June 20 and 22, when the reaches its maximum tilt away from the Sun, resulting in the shortest day south of the . These dates are determined by the precise moment when the Sun reaches its most southerly , approximately 23.44 degrees south of the . The , introduced in 1582 to reform the , accounts for the 's length of approximately 365.2422 mean solar days through a rule that adds an extra day every four years, except in certain centurial years not divisible by 400. This adjustment ensures that solstice dates remain stable within a narrow range, oscillating by up to three days (rarely four) due to the interplay of s and the exact timing of the . Without such corrections, the calendar would drift relative to the seasons by about one day every four years, but the Gregorian system's average year length of 365.2425 days introduces only a minor discrepancy of roughly 26 seconds annually compared to the current , leading to a cumulative shift of one day every approximately 3,300 years. In non-Western calendar systems, solstice dates exhibit further variations. The Chinese lunisolar calendar aligns the , commemorating the winter solstice, with the around December 21 to 23 in the , determined by the Sun's position in the zodiac. This placement ensures seasonal synchronization through periodic intercalary months. In contrast, the Islamic , consisting of 12 synodic months totaling about 354 days, drifts backward by approximately 11 days relative to the solar year each Gregorian year, causing the solstice to occur at varying lunar dates without fixed alignment to seasons. Over long timescales, the of the equinoxes—a slow wobble of Earth's rotational axis with a cycle of about 25,772 years—shifts the positions of solstices and equinoxes relative to the , but the Gregorian calendar's basis in the (defined by successive vernal equinoxes) incorporates this effect to maintain stable seasonal dates. The resulting long-term drift is minimal, with solstice timings varying by less than one day over several millennia due to the calendar's design and slight fluctuations in the tropical year's length.

Observational and scientific aspects

Measuring day length and tilt effects

The of daylight on the winter solstice varies significantly with due to Earth's , which positions the Sun at its most southerly of approximately 23.5° south. In the , locations poleward of the (about 66.5° N) experience , with zero hours of daylight as the Sun remains below the horizon for the entire day. For instance, at the , this results in 24 hours of continuous darkness. Conversely, near the , day length is roughly 12 hours; at approximately 28° N latitude, daylight duration is approximately 10 hours and 22 minutes, illustrating the variation due to Earth's axial tilt; while at higher mid-latitudes like 40° N, it may be as short as 9 hours. Conceptually, daylight duration is calculated as the period when the Sun's altitude exceeds zero degrees, determined by the observer's latitude (φ) and the Sun's declination (δ ≈ -23.5°): the sunset (ω_s) satisfies cos(ω_s) = -tan(φ) tan(δ), and the total day length is (24/π) acos[-tan(φ) tan(δ)] hours, illustrating how the tilt geometrically limits the Sun's visibility arc across the sky. This tilt also reduces the Sun's elevation at solar noon, leading to weaker insolation—the amount of received per unit area—and contributing to cooler surface temperatures that mark the onset of winter. At noon on the winter solstice, the maximum solar elevation (α) is approximately α = 90° - φ - |δ|, so at 40° N , α ≈ 26.5°, causing to strike at a shallow that spreads over a larger surface area, reducing intensity by a factor related to cos(α). This oblique incidence contrasts with summer's higher angles, initiating seasonal cooling as less is absorbed by Earth's surface. Observers have long measured these effects using simple tools like sundials, which cast their longest midday shadows on the winter solstice due to the depressed solar noon position, directly visualizing the tilt's impact on light paths. The —a figure-eight diagram of the Sun's annual path traced against a fixed point—reaches its lowest point at the winter solstice, confirming the minimal through photographic or observational records. Modern tools, such as NOAA's online solar position calculator, enable precise tracking of solar noon depression and day length by inputting latitude and date, providing data on elevation angles and twilight durations without physical instruments. In contrast to the equinoxes, where the Sun's is zero and day length approximates 12 hours at nearly all latitudes (barring effects), the winter solstice marks the annual minimum daylight in the , emphasizing the tilt's role in creating seasonal extremes rather than balance. Following the winter solstice, as the Earth's axial tilt begins to orient the Northern Hemisphere more directly toward the Sun, daylight hours gradually increase, with days lengthening by approximately 1-2 minutes per day initially. However, while overall daylight increases due to changing declination—as the sun's declination increases daily, resulting in a higher path across the sky, with shorter morning shade windows, quicker ramp to full exposure, steadily longer days, and increased insolation—sunrises continue to occur later until early January because Earth's orbital speed near perihelion causes the apparent solar day to lag via the equation of time, whereas sunsets begin advancing earlier immediately from the geometric shift, resulting in the initial extra daylight accumulating primarily in the evenings.

Prediction methods and historical calculations

Ancient astronomers relied on observational data and arithmetic techniques to approximate the timing of solstices, which mark the points when the Sun reaches its maximum or minimum . In , predictions were made using arithmetic progressions based on numerical sequences derived from long-term observations of celestial cycles, allowing for the forecasting of seasonal turning points like solstices through linear and periodic adjustments to mean motions. Similarly, ancient employed decans—groups of that rose heliacally every ten days—to divide the and align their with solar events, providing rough estimates of solstice occurrences by tracking stellar risings in relation to the Nile's flood cycle tied to . The Ptolemaic system, as detailed in Claudius Ptolemy's , utilized an eccentric model for the Sun's motion rather than full epicycles, enabling the computation of the Sun's ecliptic and subsequent to identify solstice timings when the longitude reached 90° or 270°. This geocentric framework accounted for observed irregularities in solar motion through adjustments to the deferent circle's eccentricity, yielding predictions accurate to within a day for solstices over centuries. In the Copernican heliocentric model, shifted the paradigm by placing the Sun at the center with in a (using an epicycle to approximate eccentricity), allowing of the Sun's apparent position from Earth's orbital parameters to determine solstice declinations precisely based on geometric projections. Modern predictions employ high-precision algorithms that integrate gravitational perturbations and relativistic effects for exact UTC timings of solstices. Jean Meeus's Astronomical Algorithms provides polynomial approximations for the Sun's apparent ecliptic , such as the mean : λ=280.466+36000.7698t+0.000303t2\lambda = 280.466 + 36000.7698 t + 0.000303 t^2 where tt is the time in Julian centuries from J2000.0, refined further by terms for the equation of the center, , and aberration to achieve sub-second accuracy for solstice moments when the equals 90° or 270°. The (JPL) ephemerides, generated via numerical integration of solar system dynamics, incorporate these effects along with precession and light-time corrections to produce UTC-based solstice predictions via the Horizons system, essential for space mission planning and global calendars. Contemporary forecasting benefits from software and standardized protocols that automate these computations. Tools like Stellarium implement Meeus-derived algorithms to simulate and predict solstice timings interactively, jumping directly to or solstice moments for any year. The (IAU) establishes foundational standards through the Standards of Fundamental Astronomy (SOFA) library, which includes routines for precession-nutation models and time scales to ensure consistent, high-fidelity predictions across observatories worldwide.

Climate and ecological impacts

The winter solstice marks the astronomical onset of winter in the , coinciding with the shortest day and initiating a period of declining temperatures due to the Earth's lag, where surface delays the full cooling effect despite increasing daylight post-solstice, with days getting progressively longer by gaining a few minutes of sunlight each day. In mid-latitudes, average air temperatures typically continue to drop for 2-4 weeks after the solstice, reaching seasonal minima around early , as exceeds incoming during this transition. This lag arises from the slow release of stored heat from land and surfaces, contributing to progressively colder conditions through the season. Ecologically, the solstice signals critical adaptations in biota, with reduced daylight hours triggering migration in birds such as geese and ducks, which begin southward journeys in response to photoperiod changes starting months prior but accelerating as days shorten toward the solstice. Mammals like bears and ground squirrels enter in late fall, a state of metabolic suppression that aligns with the solstice's onset of peak winter darkness, conserving energy amid food scarcity and cold. respond to shorter days and lower light intensity by entering , curtailing —rates of which can drop by over 90% in temperate species during winter—leading to leaf abscission and energy storage in roots for spring regrowth; for instance, the undergoes a seasonal molt to a thicker in late fall, enhancing insulation as solstice conditions intensify. Human societies have long integrated these solstice-driven patterns into practices, with historical in ancient civilizations relying on the —including the winter solstice—to time planting and harvesting, as shorter days prompted preparation and storage for the following year. In modern contexts, the solstice initiates heightened energy demands for heating in cold regions, where winter peaking occurs as residential and commercial consumption rises above annual averages to combat dropping temperatures, straining grids in areas like the . In the , the corresponding event is , which boosts ecological activity by maximizing daylight and warmth, enhancing and supporting surges in regions like , where native such as eucalypts exhibit peak growth and like kangaroos increase amid extended daylight. This hemispheric underscores the solstice's global role in synchronizing seasonal rhythms across ecosystems.

Ursid meteor shower

The Ursids are an annual meteor shower associated with the winter solstice period in the Northern Hemisphere, resulting from debris left by Comet 8P/Tuttle. The shower is active from December 13 to 24, with its peak typically occurring around December 22, coinciding closely with the date of the winter solstice. This temporal alignment provides observers with an additional astronomical phenomenon to view during the solstice, though the shower's occurrence is independent of the solstice itself. Under optimal conditions, up to five meteors per hour may be visible, radiating from the constellation Ursa Minor.

Historical development

Prehistoric and Neolithic evidence

Archaeological evidence from the prehistoric and periods indicates that early humans recognized and marked the winter solstice through monumental alignments and symbolic representations, likely for tracking seasonal changes essential to , such as , gathering, and agricultural planning. Megalithic structures across and the feature precise orientations to the solstice sunrise or sunset, while some cave and depict solar motifs that imply observation of celestial cycles. These artifacts, dating from the late to the (c. 10,000–3000 BCE), demonstrate sophisticated environmental awareness without written records. One of the most prominent examples is the passage tomb in Ireland, constructed around 3200 BCE during the period. The tomb's long passageway and entrance are aligned southeastward, allowing the winter solstice sunrise to penetrate a specially designed roof-box and illuminate the inner chamber, including ornate triple spiral carvings on the basin stone, for about 17 minutes. Excavations from 1962 to 1975 confirmed this intentional alignment, with supporting the construction date and evidence of ritual use through deposited artifacts from later periods. In , , built in phases from around 3000 BCE, incorporates a primary axis that aligns with the winter solstice sunset, where the sun sets between the uprights of the central when viewed from the monument's entrance. Archaeological findings at nearby reveal evidence of large midwinter gatherings, including the remains of feasted animals slaughtered around the solstice, suggesting ceremonial observances tied to the event. The , positioned outside the circle, contributes to the overall solstitial framework, though it is more prominently associated with the summer sunrise. Further afield, in (c. 9600 BCE) shows potential astronomical alignments in its T-shaped pillars and enclosures, with interpretations of carvings on Pillar 43 possibly encoding solstice-related constellations and a , supported by radiocarbon dates linking the site to the transition. Similarly, at in (c. 7000 BCE), a and megaliths align with both summer and winter solstices, coinciding with seasonal monsoons vital for pastoral life, while central tombs contain burials—such as a complete cow skeleton and cow-shaped sculptures—indicating ritual ties to these celestial markers. These sites, alongside solar motifs in some European cave art, underscore how solstice observation facilitated communal rituals and in preliterate societies.

Ancient civilizations' records

In , awareness of the winter solstice is evidenced by architectural alignments in and temples that capture on that date, reflecting an understanding of the sun's annual path. A Middle Kingdom tomb (c. 2000 BCE) in the near features a precisely oriented to the winter solstice sunrise, symbolizing the rebirth of light and its integration into funerary rituals. Similarly, the Temple complex in aligns with the winter solstice, allowing sunlight to illuminate inner sanctuaries dedicated to the sun god Amun-Ra during the shortest day. The , inscribed in royal pyramids from the late (c. 2400–2300 BCE), contain spells evoking the sun's daily renewal and journey through the (underworld), which scholars link to broader seasonal cycles including the solstices, though direct mentions are symbolic rather than observational. These texts also reference (Sirius), whose near predicted flooding, anchoring the to the solar year and implicitly framing the winter solstice as the opposite turning point of diminished light. Mesopotamian civilizations, particularly the Babylonians, recorded the winter solstice in tablets as a key marker in their astronomical compendium , compiled around 1000 BCE but drawing on earlier Sumerian traditions. The tablets describe the solstices as "stations of the sun," where the sun's daily path reaches its southernmost limit, with the winter solstice noted for the longest shadow length from a at noon—1 longer than at the . This observation served practical purposes, such as intercalating months in the to align with seasonal changes, and included detailed star lists for tracking the sun's position relative to constellations like MUL.MUL (). The system emphasized the solstice's role in dividing the year into two halves, influencing agricultural timing and omen . Greek astronomers built on earlier traditions to precisely calculate the winter solstice using instrumental methods. of (c. 190–120 BCE) employed a —a vertical rod on a horizontal plane—to measure the sun's noon altitude, determining the solstice date when the shadow length reached its annual maximum, corresponding to the sun's of about -23.5 degrees. His observations, preserved in Ptolemy's (2nd century CE), established the solstice around December 21 in the , with a length of the shortest day varying by ; at (36°N), it was roughly 9.5 hours. Roman naturalist , in his Naturalis Historia (c. 77 CE, Book 2, Chapter 8), described the winter solstice as the "shortest day" when the sun enters Capricorn, halting its southward motion for three days before reversing, a concept drawn from Greek sources and linked to agricultural calendars. Pliny noted its occurrence on the eighth day before the Kalends of January, emphasizing its role in marking the return of longer days. The documented the winter solstice in their codices, integrating it into a sophisticated system for agricultural and ritual purposes. The (c. 11th–12th century CE, with roots in Classic Maya astronomy from c. 250–900 CE) includes a seasonal table (pages 65b–69b) that tracks the 365-day haab year, aligning solstices and equinoxes with glyphs depicting solar events and day lengths. This table positions the winter solstice as a critical juncture for predicting rainy season onset, with showing the sun's "death" and rebirth to guide planting. The codex's calculations, accurate to within a day over centuries, reflect observations from sites like , underscoring the event's cosmological significance.

Medieval and early modern understandings

During the medieval period, Islamic scholars advanced the understanding of the winter solstice by building on and synthesizing ancient Greek astronomical traditions, particularly those of Ptolemy and Hipparchus. Abu Rayhan al-Biruni (c. 973–1048 CE), a Persian polymath, conducted precise observations of the solstices using instruments like the astrolabe and large rings for measuring solar altitudes. For instance, he documented observations of the winter solstice on 14 and 17 December 994 CE at Rayy, Iran, employing a sextant-like device to determine the Sun's position and calculate the obliquity of the ecliptic—the angle of Earth's axial tilt relative to its orbit—which he refined to approximately 23° 32' based on these measurements. Al-Biruni's work, such as his Tahdid Nihayat al-Amakin (Determination of the Coordinates of Places), integrated Greek geometric methods with empirical data from Islamic observatories, enabling more accurate predictions of solstice timings and their implications for calendar reforms. In medieval , monastic scholars preserved and adapted classical knowledge within a Christian framework, linking solstice calculations to ecclesiastical needs like determining 's date. The Venerable (c. 673–735 CE), an Anglo-Saxon monk, detailed these connections in his De Temporum Ratione (, c. 725 CE), where he described the winter solstice as falling within the Anglo-Saxon month of Ġēola (), spanning late December and early January, with the solstice itself around 21 December. emphasized the solstice's role in the Julian calendar's solar-lunar synchronization, using it to compute the vernal equinox (essential for ) and noting how precession gradually shifted solstice dates over centuries. His treatise bridged pagan seasonal markers with Christian computus, influencing monastic calendars across for centuries. The marked a pivotal shift with the revival of heliocentric ideas, refining solstice predictions through mathematical models that better accounted for 's orbital dynamics. Nicolaus Copernicus's (On the Revolutions of the , 1543) proposed a Sun-centered system, where the winter solstice occurs when reaches the point in its orbit farthest tilted away from the Sun due to axial obliquity. This model eliminated Ptolemaic epicycles for the Sun's motion, yielding more precise ephemerides for solstice dates and explaining variations in day length without geocentric complexities; for example, it aligned observed solstice declinations more closely with empirical data than earlier systems. Complementing this, Galileo Galilei's observations in 1610, including the and , provided empirical support for , indirectly validating the orbital geometry underlying solstice phenomena and 's 23.5° tilt as the cause of seasonal extremes. In the early (c. 1500–1800), almanacs democratized solstice knowledge, disseminating dates for practical applications in and amid colonial expansion. Printed almanacs, such as those by English astrologers like Simon Forman in the late , included solstice tables derived from Copernican refinements, advising farmers on planting cycles tied to the shortest day (e.g., preparing winter stores post-solstice). For , the British (first published by ) provided daily solar declinations peaking at the winter solstice, enabling mariners to compute via noon sights; this was crucial for transatlantic voyages, where solstice alignments helped calibrate chronometers against Greenwich time. These publications, blending astronomy with everyday utility, spread solstice awareness from European courts to colonial outposts.

Cultural and regional traditions

European and Germanic practices

In Germanic traditions, the winter solstice was marked by Yule (Old Norse jól, Anglo-Saxon geól), a midwinter feast spanning twelve days that celebrated the return of light and renewal after the darkest time of the year, with practices dating from the 4th to 10th centuries as evidenced in early medieval texts and folklore compilations. Central to Yule was the burning of the Yule log, a large oak or other hardwood selected and kindled on midwinter eve, allowed to smolder for the full twelve nights to protect the household and symbolize the sun's rebirth; sparks from the fire were invoked for prosperity, as in the Servian variant where a guest struck the log to wish for abundant livestock. Evergreen decorations, such as boughs of holly, ivy, and mistletoe, were hung in homes and halls to represent enduring life amid winter's barrenness, drawing from the sacred status of evergreens like the rowan tree in Teutonic lore, which was believed to ward off evil and ensure fertility. Celtic practices emphasized Druidic rituals tied to the solstice's symbolic renewal, with harvesting as a key ceremony described by the Roman author in the CE. Druids, clad in white robes, ascended sacred oaks on the sixth day of the new moon—often aligning with winter timing—to cut using a golden sickle, catching it in a white cloth to preserve its purity; two white bulls were then sacrificed, and the plant was hailed as an all-healing remedy for infertility and poisons, underscoring its role in during the solstice's dark period. Sites like , a prehistoric monument with astronomical alignments, were later associated with Druidic solstice gatherings for fire festivals, where the frames the winter solstice sunrise, suggesting communal rituals involving bonfires to honor the sun's turning point, though direct Druidic links stem from 18th-century antiquarian interpretations of earlier alignments. Among Slavic peoples, the winter solstice was observed through (also Koleda or Szczodre Gody), a pre-Christian festival of feasting and processions to welcome the lengthening days and banish winter spirits, documented in East Slavic chronicles from the medieval period. Groups of youths, known as , roamed villages in ritual processions, singing carols and performing dances to invoke prosperity; participants donned animal —such as those of bears, goats, or cranes—crafted from wood or to impersonate protective spirits or frighten malevolent forces, ensuring the community's safety through the long night. European solstice wove in mythical elements like , a spectral procession led by the god Wodan () thundering across winter skies during the twelve nights, gathering lost souls and foretelling doom or bounty, as compiled in 19th-century analyses of medieval Germanic tales. Similarly, the figure of (or Berchta), a white-robed alpine goddess akin to , patrolled solstice nights in Bavarian and Austrian lore, rewarding diligent spinners with abundance while punishing the lazy by slitting their bellies to stuff them with straw, embodying the season's themes of judgment and purification.

Asian and Middle Eastern customs

In , the winter solstice, known as Dongzhi in the Chinese lunisolar calendar, marks the onset of winter within the traditional 24 solar terms system, which originated around 2,500 years ago during the (770–476 BCE) but was formalized as a festival during the (206 BCE–220 CE). This day, falling on December 21 or 22, signifies the shortest daylight and the beginning of the sun's strengthening yang energy, with families gathering to eat tangyuan—glutinous rice balls symbolizing reunion and family unity due to their round shape representing wholeness. The custom of consuming tangyuan, often filled with sweet paste, promotes harmony and wards off misfortune, a practice especially prominent in southern where it evolved as a counter to the cold's isolating effects. In , the winter solstice, called , is observed through rituals emphasizing purification and health, particularly the yuzu-yu bath, where whole citrus fruits are added to hot bathwater around December 21–23. This tradition, rooted in folk beliefs, uses the fruit's aromatic oils to cleanse the body, ward off evil spirits, and prevent winter ailments like colds by warming the skin and promoting relaxation. The practice reflects Shinto-influenced customs of seasonal renewal, with the citrus scent believed to invigorate the spirit during the year's longest night. In the , particularly among Iranians with ancient Zoroastrian heritage, the winter solstice is celebrated as Shab-e Yalda, or "Night of Birth," commemorating the birth of , the deity of light and covenants, on the longest night around 20–21. Families gather to light fires symbolizing the triumph of good over darkness, sharing fruits like pomegranates and watermelons to represent life's vitality and staying awake to protect against malevolent forces, a custom tracing to pre-Islamic Zoroastrian rituals emphasizing renewal. Among the Yazidi community, who share Indo-Iranian roots, the solstice aligns with a three-day fast known as Rojîyê Êzî, ending in the Feast of Ezid (Cejna Êzî), a period of reflection and communal feasting to honor emerging from winter's depths, observed in late . In , the winter solstice influences the Indian festival of , observed around January 14 when the sun enters Capricorn (Makar), slightly offset but marking the celestial northward journey () that begins at the solstice. Celebrations feature kite flying across regions like and , symbolizing the soul's ascent toward enlightenment, while sesame-based sweets such as tilgul ladoos—made from roasted sesame seeds and —are exchanged to foster sweetness in relationships and provide nourishment during the transitional cold. These practices, tied to Vedic astronomy, highlight the solstice's role in agricultural cycles and solar reverence.

Indigenous and Southern Hemisphere observances

Indigenous peoples around the world have long observed the winter solstice as a pivotal moment for renewal, seasonal transition, and connection to cosmic and earthly cycles, with practices varying by hemisphere where the event falls in for the and for the Northern. These observances often integrate astronomical knowledge, , and rituals to mark agricultural shifts and spiritual rebirth. In , Aboriginal communities incorporate the winter solstice (around ) into broader seasonal calendars tied to Dreamtime narratives, using celestial features like the " in the Sky"—a constellation formed by dark nebulae in the —to signal environmental changes. For many groups, such as the Euahlayi, the 's position in the sky during cooler months aligns with winter patterns, guiding hunting, gathering, and ceremonial timing, though it more prominently indicates emu breeding in adjacent seasons. Stone arrangements, like the site near , Victoria, dating back potentially 11,000 years, align with solstice sunrises and sunsets to predict weather and ritual schedules, reflecting sophisticated embedded in oral traditions. Among , the June winter solstice is central to , the "Festival of the Sun," revived by Quechua descendants of the Inca in . Held annually on June 24 in , this multi-day event honors , the sun god, through processions, music, dances, and offerings to ensure the sun's return and bountiful harvests, echoing pre-colonial Inca rituals documented in chronicler accounts. Participants, including actors in traditional attire, reenact ceremonies at sacred sites like , emphasizing communal gratitude and agricultural renewal in the Andean highlands. In North America, the Hopi people of northeastern Arizona conduct the Soyal ceremony, a 16- to 20-day winter solstice ritual beginning around December 21, focused on purification, prayer, and welcoming kachinas—spiritual beings representing ancestors and natural forces. Led by religious leaders in kivas (underground ceremonial chambers), it features dances, storytelling, and the distribution of pahos (prayer sticks) to invoke harmony and the sun's strengthening, symbolizing the world's emergence and cyclical renewal. Among the Lakota of the Great Plains, the December solstice holds sacred significance as a time for reflection, prayer circles, and storytelling, tying into broader renewal themes seen in their summer Sun Dance, where participants endure physical trials to foster community healing and cosmic alignment. The of in mark the winter solstice with the Goru ceremony, a celebration culminating in rituals that honor ancestral spirits and agricultural abundance using a large ceremonial vessel symbolizing a mythical ark. Performed communally with masks, dances, and invocations.

Religious and festival connections

Pre-Christian pagan celebrations

In , the was a prominent festival held from December 17 to 23, honoring Saturn, the god of agriculture and sowing, with rituals that symbolically loosened the woolen bonds on his temple statue to represent liberation and renewal. The celebrations began with sacrifices and a public banquet at the , followed by widespread feasting, , and the exchange of gifts such as wax candles and small figurines, all timed around the winter solstice to invoke hopes for the coming spring harvest. A key feature was the temporary , where slaves were treated as equals, dined before their masters, and wore the pileus cap of , reflecting Saturn's association with a mythical of equality. Among the Norse peoples, the festival of Jul (Yule) marked the winter solstice around December 21, serving as a midwinter feast that blended themes of light's return, fire, and communal feasting to combat the season's darkness. Rituals included sacrifices, often of cattle or other livestock, offered to —known as Jolnir during this time—to ensure the sun's rebirth and prosperity, with the meat providing sustenance for extended banquets that could last up to twelve days. Evergreens played a symbolic role, representing , the world tree connecting the realms, and were incorporated into practices like the , a large oak trunk burned gradually to ward off evil and symbolize enduring life amid winter's death. Celtic traditions around Samhain, though primarily an autumnal cross-quarter festival midway between the fall equinox and winter solstice, incorporated solstice-adjacent elements through fire rituals aimed at purification and protection as winter approached. Communities lit massive bonfires on hilltops, believed to cleanse the air of malevolent spirits and renew the land's fertility, with participants driving cattle between the flames or leaping over them to gain blessings for health and livestock survival through the cold months. These practices underscored Samhain's role in honoring the thinning veil , blending harvest thanksgiving with preparations for solstice darkness.

Abrahamic and other religious ties

In , the date of for the was calculated by early as nine months after the on , coinciding with the vernal and leading to alignment with the winter solstice. , around 200 CE, explicitly linked this date to the solstice through an inscribed statue that positioned Christ's birth on , emphasizing as the "true sun" returning light after the shortest day. This symbolism portrays the solstice as a theological marker of overcoming darkness, independent of direct pagan adoption but resonant with seasonal renewal. Judaism's , beginning on the 25th of , falls near the winter solstice in the , creating a coincidental overlap where its candle-lighting ritual counters the winter darkness. Historically, however, commemorates the Maccabean rededication of the Temple in 164 BCE and has no direct astronomical tie to the solstice, though the timing ensures observance during the year's shortest days. Islam lacks a formal connection to the winter solstice, but ancient Persian traditions, including elements of solar renewal, influenced post- customs like Shab-e Yalda, the of the solstice celebrated with vigils against encroaching darkness. Some Sufi practices incorporate winter night vigils for spiritual contemplation, echoing these pre- Persian roots where the longest night symbolized the triumph of light, as seen in Mithra's birth. In , marks the sun's northward journey beginning immediately after the winter solstice around December 21, viewed as an auspicious period for spiritual practices and harvest, symbolizing the onset of longer days and enlightenment. The Bahá'í faith, while not observing the solstice as a holy day, draws on it metaphorically in writings to reflect on cycles of spiritual renewal, with the longest night prompting contemplation of unity and the emergence of light from darkness.

Modern secular and revived festivals

In contemporary society, the winter solstice has inspired various secular celebrations that emphasize themes of , renewal, and well-being without religious connotations. The established the International Day of the Celebration of the Solstice on June 21 in 2019 (resolution A/RES/73/300) to recognize the solstices' role in , , and food production systems. Solstice yoga gatherings have also gained popularity, particularly in wellness communities, where practices such as gentle breathwork and mindful movement are used to promote and personal renewal during the shortest days. For instance, events like "Solstice Awakening" in incorporate and self-massage to foster emotional balance and , drawing on the solstice's symbolism of transitioning from darkness to . Similarly, mental health advocates frame the solstice as a period for honoring natural rhythms, encouraging rest and resilience to combat seasonal affective challenges. Neopagan and Wiccan communities have revived ancient-inspired rituals as modern festivals centered on the winter solstice, focusing on communal harmony and the return of light. These often include decorating trees with symbolic ornaments to represent life's persistence, lighting candles or a for warmth and rebirth, and ceremonies featuring chants and drumming to invoke seasonal energies. Such practices, adapted for contemporary settings, emphasize environmental connection and personal growth, with many groups hosting inclusive gatherings that blend , feasting, and gift exchanges. A key site for these revivals is in , where organized solstice gatherings by druids and pagans have occurred since the early , evolving into large public events that attract thousands annually to witness the sunrise alignment and promote themes of renewal. Scientific observances of the winter solstice highlight its astronomical importance through educational and participatory events. Planetariums worldwide offer special shows simulating the solstice's , such as the Earth's causing the shortest day in the , often combined with live narrations on seasonal changes. groups organize stargazing watches, using telescopes to observe the solstice's effects on constellations and planetary positions, fostering public engagement with ; for example, the host viewings to mark the event's precise timing at 1:21 a.m. . has recognized several cultural sites for their solstice alignments, enhancing global appreciation of these phenomena, including in Ireland, where the winter sunrise illuminates its chamber, and in , USA, noted for its earthen enclosures' solar orientations as part of the Hopewell Ceremonial Earthworks. In the , where the marks rather than winter, celebrations contrast sharply with themes of introspection and light-seeking by embracing outdoor festivities and abundance. In and , midsummer parties often feature barbecues, gatherings, and bonfires under long daylight hours, symbolizing vitality and community joy. These gatherings highlight the solstice's role in seasonal reversal, with adaptations in pagan communities shifting to for the actual winter solstice while treating as a time of exuberant midsummer revelry.

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