what is the average amount of rainfall in deserts
One of the most well-known deserts, the  Sahara, is split into two. The first half receives on average less  than 20mm of rainfall a year, while the other half see's up to  100mm in a year.   A less well known desert is Antarctica. Many expect it to simply be  an area of ice, however due to the lack of rainfall it is classed  as a desert.