Las Vegas Weather in September
In September, Las Vegas, Nevada usually sees the last of summer's 100-degree Fahrenheit temperatures (over 37 degrees Celsius).
This page gives detailed information on the typical September temperature, precipitation, sun, humidity, wind and storms for Las Vegas. The numbers here are historical averages based on climate data gathered at the McCarran International Airport, located near the south end of the Las Vegas Strip.
Temperature
| 95 °F | September average high | 35 °C |
| 72 °F | September average low | 22 °C |
| 24 days | 90 °F max. or more (32 °C) |
| 13 days | 70 °F min. or less (21 °C) |
Nearly every day in September heats up to over 80 °F (26 °C) in Las Vegas. The city averages 8 days this month when the thermometer reaches into the 100s °F (over 37 °C).
At night, the thermometer dips to 60 °F (16 °C) or below on 2 days. Normally September does not get as cold as 50 °F (10 °C).
Rain
| 0.3 in | total precipitation | 8 mm |
| 2 days | of rain |
Most years, Las Vegas gets less than 0.4 inches (11 mm) of rain in September. About once every four years, the city receives no rain at all this month.
Sun
| 91 % | sunshine |
| 22 days | clear skies |
The sun's rays reach the ground in Las Vegas during 91 percent of daylight hours on average in September, for a total of 338 hours in the month. Typically on 22 days this month the sky is mainly clear, with at most 30 percent cloud cover.
Sunlight in September at Las Vegas lasts for 12 hours and 22 minutes a day on average. The longest day of the month is the 1st with 12 hours and 55 minutes of daylight. By the end of the month, the days have shortened to 11:50 from sunrise to sunset. These durations can vary by a minute or two from year to year.
Humidity
| 25 % | September average humidity |
The relative humidity in Las Vegas during September usually peaks at 34 percent in the morning then drops to 17 percent around mid afternoon.
| Local Time | 1 am | 4 am | 7 am | 10 am | 1 pm | 4 pm | 7 pm | 10 pm |
| Humidity % | 30 | 34 | 32 | 23 | 18 | 17 | 21 | 26 |
Wind
| 8.9 mph | September wind speed average | 14.3 kph |
September is a little less windy than most other months in Las Vegas.
Storms
| 1 day | rainfall of 0.1 inches (2.5 mm) or more |
| 2 days | with thunderstorms in September |
About once every five years, Las Vegas receives as much as an inch (25 mm) of rain in one day during September.
Reference
The weather data here are long-term averages provided by the US National Centers for Environmental Information (NCEI). Temperature and precipitation are 1991-2020 normals while humidity and thunderstorms are 1961-1990 normals.