The Mojave desert is a diverse geographic region with all the climatic extremes common to a true desert. Deserts are typically defined as an area which has minimal rainfall. The average precipitation in southern Nevada is 4.25 inches per year, which averages out to a meager .35 inches per month. However, many months of the year fair far less than this amount. It is not uncommon for individual storms to supply a major percentage of the annual amount.
Temperature extremes are the norm.
The Las Vegas valley may experience 152 days of temperatures over 90 F. During this period, nearly 100 days may reach the 100 F mark and approximately 30 days will reach temperatures of 110 F or more. The winter months are more gentle, with an average of 35 total days with temperature below freezing. The average first frost is around November 12th and the average last frost is March 17th. Coupled with the wide range of temperatures are numerous days of high winds and intense sunlight, all of which make gardening a real challenge in southern Nevada. National Weather Service, Las Vegas - See the current forecast in Las Vegas.