The Las Vegas 100 Degree Season
Introduction
100F/38C unofficially marks the beginning and ending of summer for Las Vegas. Once it gets to 100F there is no turning back since it usually occurs 75 more times over the summer. The last 100F of the season is a good sign that fall is coming at last. In this blog post I’ll talk more in-depth about some of the stats behind 100F in Las Vegas.
First/Last Dates
The average first date of 100F is May 24th but that’s just an average. It has happened as early as May 1st. It can also happen as late as June 30th which is what happened in 2023, a very strange year. At the end of the summer, the last 100F happened as early as August 30th but usually they keep happening well into September. The normal last 100F is September 16th. Amazingly, the latest 100F is in October when it happened on the 4th in 1947. Not very fall like!
Temperatures in Las Vegas soar over 100F/38C on average 75 times each summer.
100 Degree Season
The date of the first 100F to the last 100F is what I call the 100 degree season. It has varying lengths if it starts late or ends early or vice versa. The normal number of days for the 100 degree season is 114 or about three and half months. Not every day over that span is over 100F - in fact, 1/3 are not. Even summer has its ups and downs but mainly the early and late parts of the summer are when temperatures fall below 100F. In 2020, the 100 degree season lasted an incredible147 days from May 6th to October 1st. Ironically, the shortest 100 degree season happened just three years later in 2023. That year, as I said previously, didn’t even start until June 30th and it ended a little early on September 9th making it only 70 days long.
Records
Here are some interesting records about triple digit heat in Las Vegas.
The greatest number of days over 100 - 100 days in 1947
The fewest number of days over 100 - 44 days in 1965
Month with the most 100+ days - July (26 on average)
Longest continuous stretch of 100F+ - 66 days from June 27 - August 31st
Hottest temperature ever - 117F - Five times in history (2021, 2017, 2013, 2005, 1942)
The trend for 100F+ days is very steady. The number of days is neither increasing or decreasing.
Conclusion
May is usually the start of the 100 degree season which is unofficially Las Vegas’ real summer. The number of days from the first to the last 100 is what I consider the 100F degree season and it has varying lengths. Generally it last about 3 and half months in which the high gets to 100F an average of 75 times. While the number of days varies quite a lot, the trend remains steady.
