- full-arid climate: Precipitation < Evaporation applies to10 to 12 months in the year
- semiarid climate: Precipitation < Evaporation applies to 6 to 9 months in the year.
Most dry regions lie in the subtropical desert belt, because the trade winds arrive only up to the so-called horse latitudes, but give it arid climates likewisein other regions, for example in many high mountains and „the polar deserts “.
Also on the planet Mars prevails a kind desert climate, which despite the very thin CO 2 - atmosphere often long-continuous sandstorms causes. This led also to the fact that „the Mars channels “for many decades as natural or artificial Wasserrinnen were interpreted.