Las Vegas Weather In September
Las Vegas Weather in September is all about cooling temperatures. The average high starts around 100°F on September 1st, and it's about 85°F on the 30th. The great weather at the end of the month makes late September a great time time to be in Las Vegas, especially at the end of the month.
If you are in Las Vegas during the first week of September be prepared for hot weather, but by the middle of September golfing, tennis, or hiking should be more enjoyable.
Suggested dress includes shorts and bathing suits, and by the middle of the month you will want to bring a light jacket just in case of cool evenings and early mornings. Wet weather clothes will probably not be needed.