The mesosphere is the region of the atmosphere located between the stratosphere and the thermosphere, between 50 and 90 km, in which temperature decreases with height. The farther away you get from the earth, the thinner the atmosphere gets. The total heat content of a system is directly related to the amount of matter present, so it is cooler at higher elevations. The heating of the earth itself also plays a role. The Earth's surface gets heat from the sun. As a result, the surface gets heated up. The air close to the surface starts becoming hot and later, one by one, different layers of air at higher elevation receive heat. Therefore, as we move upward from sea-level, the temperature of air decreases. When cool air descends, it warms. Since it can then hold more moisture, the descending air will evaporate water on the ground. Air moving between large high and low pressure systems creates the global wind belts that profoundly affect regional climate.

The farther away you get from the earth, the thinner the atmosphere gets. The total heat content of a system is directly related to the amount of matter present, so it is cooler at higher elevations. The heating of the earth itself also plays a role. Temperature increases as you gain altitude in the stratosphere and the thermosphere. Temperature decreases as you gain altitude in the troposphere and mesosphere. As the density of the gases in this layer decrease with height, the air becomes thinner. Therefore, the temperature in the troposphere also decreases with height in response. As one climbs higher, the temperature drops from an average around 62°F (17°C) to -60°F (-51°C) at the tropopause. When cool air descends, it warms. Since it can then hold more moisture, the descending air will evaporate water on the ground. Air moving between large high and low pressure systems creates the global wind belts that profoundly affect regional climate. As the pressure decreases, air molecules spread out further (i.e. air expands) and the temperature decreases. If the humidity is at 100 percent the temperature decreases more slowly with height. Sometimes, especially during cold winter nights the temperature increases with the altitude. This is mainly due to the rapid radiation from the ground and on account of the flow of heavy cold air down the valley. In the atmosphere, the distribution of moisture and the lower air pressure at progressively higher altitudes result in decreasing temperatures with height up to the tropopause, with the rate of decrease depending on geographical factors and meteorological conditions.