Desert, term applied to regions on the earth that are characterised by less than about 250mm of annual rainfall, and, in many cases an evaporation rate that exceeds precipitation, and a high average temperature. Because of the lack of moisture in the soil and the low humidity in the atmosphere, most of the sunlight penetrates to the ground. Daytime temperatures have reached 57.8 Degrees Celsius on the 13th of September 1922, this was the highest ever recorded in Libya. On the other hand at night the temperature can drop to near freezing. Deserts are found in ever continent throughout the globe from Africa to the cold plains of Northern China.

Hot deserts extend all around the world in two belts, to the north and south of the tropical zone around the world's equator. Further from the equator, north and south are the cold deserts, and even further are the ice-covered...