It is an area with an annual rainfall of fewer than 25 centimeters.
A desert is defined not by temperature but by the sparse amount of water found in a region.
An area with an annual rainfall of fewer than 25 centimeters (9.75 inches) generally qualifies as a desert.
Deserts can occur in colder areas too.
If you add in a bit of wind to accelerate evaporation at the surface, and the continental regions below become extremely arid owing to the lack of available moisture. Deserts thus become dry.
