All deserts are dry. Dryness is part of their definition. But while all deserts may be dry, they are not all equally dry. The driest desert on earth is the Atacama desert in Chile. The Atacama desert gets an average of less than .01 centimeters (.004 inches) of rain every year. Sometimes years will go by between rain storms. In fact, there are some places in the Atacama desert where it has not rained for over 400 years!