Mummy
The night was chilly.
Well, it was a desert, after all, it was known for its ferocious heat in the daytime while biting cold at nighttime.
It is sand, which turns the entire phenomenon hot. Sand cannot hold the heat. It acts like a mirror to the sun. During the daytime, it stays warm, and when the Sun is absent it loses all its heat making the nights colder. There is nothing in the desert that can either absorb heat from the sun or hold it on the surface when the sun is set. Summer nights might be a little warm, but winter nights have temperatures below the freezing point. The heat from the sky gets radiated into space and hence the temperatures plummet low during night times. The desert animals and reptiles come out during night times. When it comes to normal places, it is the water vapor and carbon-di-oxide present in the atmosphere that keeps our nights warm. As there are no trees and water in the deserts, there is no source of these to keep the temperature warm.