Atmospheric temperature is a measure of temperature at different levels of the Earth's atmosphere. It is governed by many factors, including incoming solar radiation, humidity, and altitude. The abbreviation MAAT is often used for Mean Annual Air Temperature of a geographical location.

The temperature of the air near the surface of the Earth is measured at meteorological observatories and weather stations, usually using thermometers placed in a shelter such as a Stevenson screen—a standardized, well-ventilated, white-painted instrument shelter. The thermometers should be positioned 1.25–2 m above the ground. Details of this setup are defined by the World Meteorological Organization (WMO).

A true daily mean could be obtained from a continuously recording thermograph. Commonly, it is approximated by the mean of discrete readings (e.g. 24 hourly readings, four 6-hourly readings, etc.) or by the mean of the daily minimum and maximum readings (though the latter can result in mean temperatures up to 1 °C cooler or warmer than the true mean, depending on the time of observation).

The world's average surface air temperature is about 14 °C.

Temperature varies greatly at different heights relative to the surface of the Earth; it is this variation which characterizes the four layers that exist in the atmosphere. These layers are the troposphere, stratosphere, mesosphere, and thermosphere.

The troposphere is the lowest of the four layers and extends from the surface of the Earth to about 11 km (6.8 mi) into the atmosphere, where the tropopause (the boundary between the troposphere stratosphere) is located. The width of the troposphere can vary depending on latitude: for example, the troposphere is thicker in the tropics (about 16 km (9.9 mi)) because the tropics are generally warmer, and thinner at the poles (about 8 km (5.0 mi)) because the poles are colder. Temperatures in the atmosphere decrease with height at an average rate of 6.5 °C (11.7 °F) per kilometer. Because the troposphere experiences its warmest temperatures closer to Earth's surface, there is great vertical movement of heat and water vapour, causing turbulence. This turbulence, in conjunction with the presence of water vapour, is the reason that weather occurs within the troposphere.

Following the tropopause is the stratosphere. This layer extends from the tropopause to the stratopause, which is located at an altitude of about 50 km (31 mi). Temperatures remain constant with height from the tropopause to an altitude of 20 km (12 mi), after which they start to increase with height. This is referred to as an inversion, and it is because of this inversion that the stratosphere is not turbulent. The stratosphere receives its warmth from the sun and the ozone layer which absorbs ultraviolet radiation.

The next layer, the mesosphere, extends from the stratopause to the mesopause (located at an altitude of 85 km (53 mi)). Temperatures in the mesosphere decrease with altitude, and are the coldest in the Earth's atmosphere. This decrease in temperature can be attributed to the diminishing radiation received from the Sun, after most of it has already been absorbed by the thermosphere.