Las Vegas' climate is a subtropical arid climate (Koppen climate classification BWh), typical of the Mojave Desert in which it lies. The city enjoys abundant sunshine year-round and has an average of about 300 sunny days per year and more than 3800 hours of sunshine, with about 4.2 inches of rainfall, which on average occurs on 29 days per year.
The summer months of June through September are very hot and mostly dry with average daytime highs of 94 to 104 °F (34 to 40 °C) and nighttime lows of 69–78 °F (21–26 °C). There are an average of 133 days per year above 90 °F (32 °C), and 72 days above 100 °F (38 °C), with most of the days in July and August exceeding that benchmark. However, humidity is very low and often under 10%.
Las Vegas' winters are of short duration and the season is generally mild, with daytime highs near 60 °F (16 °C) and nighttime lows around 40 °F (4 °C). The mountains surrounding Las Vegas accumulate snow during the winter but snow is rare in the Las Vegas Valley itself. Several years apart, however, snow has fallen in the valley. Temperatures can sometimes drop to freezing 32 °F (0 °C) but winter nighttime temperatures will rarely dip below 30 degrees.
Annual precipitation in Las Vegas is roughly 4.5 in (110 mm), which mainly occurs during winter but is not uncommon anytime of the year.