A typical September features normal highs dropping from the mid 80s down into the mid 70s by the end of the month, and lows falling from the mid 60s to the mid 50s.
We still get hot weather in September. We normally see about three 90° days, and the hottest September day was 103°. In fact, September 2 of last year had a new record high of 101°.
Rainfall is usually pretty decent, totaling over four inches in a normal September.
Autumn arrives on September 23, and we continue to lose about two to three minutes of daylight each day.