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Hub AI
Daylight saving time AI simulator
(@Daylight saving time_simulator)
Hub AI
Daylight saving time AI simulator
(@Daylight saving time_simulator)
Daylight saving time
Daylight saving time (DST), also referred to as daylight savings time, daylight time (United States and Canada), or summer time (United Kingdom, European Union, and others), is the practice of advancing clocks to make better use of the longer daylight available during summer so that darkness falls at a later clock time. The standard implementation of DST is to set clocks forward by one hour in spring or late winter, and to set clocks back by one hour to standard time in the autumn (or fall in North American English, hence the mnemonic: "spring forward and fall back").
In several countries, the number of weeks when DST is observed is much longer than the number devoted to standard time.
As of 2023, around 34 percent of the world's countries use DST, primarily in Europe and North America. Some countries observe it only in some regions. Canada largely observes DST, with the exceptions of Yukon, most of Saskatchewan, and parts of Nunavut, British Columbia and Quebec. It is observed by four Australian states and one territory. In the United States, it is observed by all states except Hawaii, Arizona (within the latter, however, the Navajo Nation does observe it), and the U.S. Territories.
Historically, several[examples needed] ancient societies adopted seasonal changes to their timekeeping to make better use of daylight; Roman timekeeping even included changes to water clocks to accommodate this. However, these were changes to the time divisions of the day rather than setting the whole clock forward. In a satirical letter to the editor of the Journal de Paris in 1784, Benjamin Franklin suggested that if Parisians could only wake up earlier in the summer they would economize on candle and oil usage, but he did not propose changing the clocks. In 1895, New Zealand entomologist and astronomer George Hudson made the first realistic proposal to change clocks by two hours every spring to the Wellington Philosophical Society, but this was not implemented until 1928 and in another form. In 1907, William Willett proposed the adoption of British Summer Time as a way to save energy; although seriously considered by Parliament, it was not implemented until 1916.
The first implementation of DST was by Port Arthur (today merged into Thunder Bay), in Ontario, Canada, in 1908, but only locally, not nationally. The first nation-wide implementations were by the German and Austro-Hungarian Empires, both starting on 30 April 1916. Since then, many countries have adopted DST at various times, particularly since the 1970s energy crisis.
Industrialized societies usually follow a clock-based schedule for daily activities that do not change throughout the course of the year. The time of day that individuals begin and end work or school, and the coordination of mass transit, for example, usually remain constant year-round. In contrast, an agrarian society's daily routines for work and personal conduct are more likely governed by the length of daylight hours and by solar time, which change seasonally because of the Earth's axial tilt. North and south of the tropics, daylight lasts longer in that hemisphere's summer and is shorter in that hemisphere's winter, with the effect becoming greater the farther one moves away from the equator. DST is of little use for locations near the Equator, because these regions see only a small variation in daylight over the course of the year.
After synchronously resetting the clocks in a region to one hour ahead of standard time in spring in anticipation of longer daylight hours, individuals following a clock-based schedule will be awakened an hour earlier in the solar day than they would have been otherwise. They will begin and complete daily work routines an hour earlier; in most cases, they will have an extra hour of daylight available to them after their workday activities.
The clock shift is partly motivated by practicality. At the summer solstice, in American temperate latitudes, for example, the sun rises around 04:30 standard time and sets around 19:30. Since most people are asleep at 04:30, it is seen as practical to treat 04:30 as if it were 05:30, thereby allowing people to wake closer to the sunrise and be active in the evening light, as the sun under DST sets an hour later (20:30).
Daylight saving time
Daylight saving time (DST), also referred to as daylight savings time, daylight time (United States and Canada), or summer time (United Kingdom, European Union, and others), is the practice of advancing clocks to make better use of the longer daylight available during summer so that darkness falls at a later clock time. The standard implementation of DST is to set clocks forward by one hour in spring or late winter, and to set clocks back by one hour to standard time in the autumn (or fall in North American English, hence the mnemonic: "spring forward and fall back").
In several countries, the number of weeks when DST is observed is much longer than the number devoted to standard time.
As of 2023, around 34 percent of the world's countries use DST, primarily in Europe and North America. Some countries observe it only in some regions. Canada largely observes DST, with the exceptions of Yukon, most of Saskatchewan, and parts of Nunavut, British Columbia and Quebec. It is observed by four Australian states and one territory. In the United States, it is observed by all states except Hawaii, Arizona (within the latter, however, the Navajo Nation does observe it), and the U.S. Territories.
Historically, several[examples needed] ancient societies adopted seasonal changes to their timekeeping to make better use of daylight; Roman timekeeping even included changes to water clocks to accommodate this. However, these were changes to the time divisions of the day rather than setting the whole clock forward. In a satirical letter to the editor of the Journal de Paris in 1784, Benjamin Franklin suggested that if Parisians could only wake up earlier in the summer they would economize on candle and oil usage, but he did not propose changing the clocks. In 1895, New Zealand entomologist and astronomer George Hudson made the first realistic proposal to change clocks by two hours every spring to the Wellington Philosophical Society, but this was not implemented until 1928 and in another form. In 1907, William Willett proposed the adoption of British Summer Time as a way to save energy; although seriously considered by Parliament, it was not implemented until 1916.
The first implementation of DST was by Port Arthur (today merged into Thunder Bay), in Ontario, Canada, in 1908, but only locally, not nationally. The first nation-wide implementations were by the German and Austro-Hungarian Empires, both starting on 30 April 1916. Since then, many countries have adopted DST at various times, particularly since the 1970s energy crisis.
Industrialized societies usually follow a clock-based schedule for daily activities that do not change throughout the course of the year. The time of day that individuals begin and end work or school, and the coordination of mass transit, for example, usually remain constant year-round. In contrast, an agrarian society's daily routines for work and personal conduct are more likely governed by the length of daylight hours and by solar time, which change seasonally because of the Earth's axial tilt. North and south of the tropics, daylight lasts longer in that hemisphere's summer and is shorter in that hemisphere's winter, with the effect becoming greater the farther one moves away from the equator. DST is of little use for locations near the Equator, because these regions see only a small variation in daylight over the course of the year.
After synchronously resetting the clocks in a region to one hour ahead of standard time in spring in anticipation of longer daylight hours, individuals following a clock-based schedule will be awakened an hour earlier in the solar day than they would have been otherwise. They will begin and complete daily work routines an hour earlier; in most cases, they will have an extra hour of daylight available to them after their workday activities.
The clock shift is partly motivated by practicality. At the summer solstice, in American temperate latitudes, for example, the sun rises around 04:30 standard time and sets around 19:30. Since most people are asleep at 04:30, it is seen as practical to treat 04:30 as if it were 05:30, thereby allowing people to wake closer to the sunrise and be active in the evening light, as the sun under DST sets an hour later (20:30).
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