What makes deserts so cold in the night when they are so hot during the day?
Answer… Deserts have extreme, fluctuating temperatures because they are so dry, meaning the air above a desert has very low humidity. Humidity is water vapor in the air, and it has the ability to insulate the land – that is, maintain temperatures. The air above a temperate forest, for example, may have 80% humidity or more during the day. This water reflects and absorbs energy from sunlight. At night the water acts like a blanket, trapping heat inside the forest. The air humidity in a desert is usually only 10-20%. This means that during the day, a lot of energy from the sun reaches the ground and heats up the air, often to very high temperatures. In the desert, is about twice as much solar radiation as in more humid regions. But at night, this heat cannot be held by the low humidity or by trees and other vegetation, so the air temperature cools down rapidly. Deserts are so dry there that some rain actually evaporates before it hits the ground. Deserts can be very cold too. Some dese