What is the criteria for someplace being called a desert?
A desert is the name given to any geographical location that typically receives little or no rainfall in a given years time. Deserts typically are barren areas, with little or no vegetation to speak of. They are hard to live in, due to the lack of water and vegetation. Rainfall for true deserts is 250 millimeters (10 inches) anually or less. For semidesert areas, a range of 250 to 400 millimeters (10 to 16 inches) is considered the norm. Deserts may also be areas where water is lost due to evaporation or transpiration more rapidly than the precipitation can replace it. Arizona has high temperatures but low humidity, so there is lots of room for the rain that does fall to evaporate quickly back into the air. Deserts may exist in both hot temperatures and cold temperatures. There are areas of the Himilayan mountains that are barren due to the low amount of precipitation that falls annually.