Deserts become cold at night primarily because the air is so dry that heat escapes rapidly at night.
During the day, deserts absorb a significant amount of heat from the sun, leading to average temperatures that can reach around 38°C. However, the lack of moisture in the desert air plays a crucial role once the sun sets.
The Impact of Dry Air
Unlike humid environments where water vapor in the atmosphere can trap heat, the extremely dry air over deserts acts like a poor insulator. This means that the heat absorbed by the ground and air during the day is not retained effectively after dark. Instead, this heat is radiated back into space quickly.
Extreme Temperature Swings
This rapid escape of heat results in dramatic temperature fluctuations between day and night. The reference notes that the temperature in the desert can change drastically. While the daytime average is about 38°C, temperatures in some deserts can plummet significantly, getting down to -4°C at night. This wide variation highlights the effect of dry air on thermal regulation.
This intense cooling is a direct consequence of the dry atmosphere's inability to hold onto the warmth gathered during the sunny hours.
