Las Vegas reaches at least 100 degrees, on average, 70 days a year. The hot season usually starts around early June and lasts until mid-September. It rarely jumps above 110 during that time, and even more rarely, exceeds 115. But there can be long streaks of triple-digits.

Las Vegas experiences extreme desert heat primarily during the summer months of June, July, August, and early September. July is consistently the hottest month, with average daytime highs reaching approximately 41°C (106°F), though temperatures frequently soar above 46°C (115°F) during heatwaves. August follows closely with similar high temperatures and often higher humidity due to the southwestern monsoon season, which can bring sudden afternoon thunderstorms. Even in June, the "dry heat" starts to become intense, with averages around 38°C (100°F). By mid-September, the temperatures begin to moderate, but "triple-digit" days are still common in the first two weeks. During these peak summer months, the sun is exceptionally powerful, and the heat often radiates from the asphalt and buildings long after sunset, keeping nighttime lows in the high 20s or low 30s Celsius (80s Fahrenheit). Travelers are advised to stay hydrated, seek shade, and plan outdoor activities for the early morning or late evening, as the midday sun can be dangerous for those not acclimatized to the Mojave Desert's climate.