Geography of Las Vegas
Las Vegas is situated on the arid desert floor within Clark County. The surrounding environment is dominated by desert vegetation and some wildlife, and the area is subject to torrential flash floods. Enabling the rapid population expansion was a major addition to the city's sewage treatment capacity. The sewage treatment expansion resulted from a U.S. Environmental Protection Agency grant funding 2008 programs to analyze and forecast growth and environmental impacts through the year 2019.
The city is in an arid basin surrounded by dry mountains. City elevation is around 2,030 ft (620 m) above sea level. The Spring Mountains lie to the west. Much of the landscape is rocky and dusty. Within the city, however, there are many lawns, trees and other greenery. Due to water resource issues, there is now a movement to encourage xeriscapes. Another part of the water conservation efforts include scheduled watering groups for watering residential landscaping. According to the United States Census Bureau, the city has a total area of 131.3 sq mi (340 km2), of which 131.2 sq mi (340 km2) is land and .1 sq mi (0.26 km2) of it (0.04%) is water.
Climate
Las Vegas' climate is an arid, desert 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.