Nevada is the driest state in America. It has an average annual rainfall of just about 7 inches. The wettest part receives about 40 inches of rain per year. Las Vegas, being at the heart of the hottest, harshest desert in North America, recevies less than 4 inches of rain per year. Las Vegas has blue skies pretty much almost all year around with more than 300 sunny days. May to September are the hottest months and July and August can be extremely hot, with temperatures over 100ºF, even though eveything is air-conditioned, walking around can be difficult. Winters are cooler but still warm and pleasant, but sometimes temperatures can drop below freezing during the night in December and January.