Which biome is very hot during the day and cold at night?

Answer 1

The sky above the desert is usually very clear (unless of course there is a sandstorm).

During the day in hot deserts, the sun rises to a very high altitude, possibly reaching zenith depending on the context - which makes the temperature rise to more than 100 degrees Fahrenheit.

At night time, once the sun is below the horizon, the cloudless sky radiates all the heat back into space therefore the temperature plummets to around 40 degrees Fahrenheit, thus the sun is as low in the desert at night as it is at solar noon at both poles in the winter!

This is also the same reason why other bodies (such as Mercury and the Moon) also have very high daytime temperatures (and very low nighttime temperatures).

Answer 2

Some deserts can be quite hot during the day. Once the sun sets the temperature can quickly become quite chilly.

Answer 3

Most hot deserts fit that description.