depends.....DH thinks it's hot, i think it's perfect then again, i can't handle going between late-oct thru early april - sun beating on the shoulders IS vacation for me
average low is 72, average high is 90 - a few degrees cooler (and less crowded, which makes heat more tolerable, imho) than most of summer.
unlike the summer months, sept tends to get a bit cooler in the last weeks. the daily 4pm rain shower is almost a given, which helps cool things down a bit. average rainfall is about double of october's (but lower than june-aug).
hth
Weather can still reach 90s that time and humidity still on the high side. Absent a hurricane, risk of rain is usually a few 30 minute thunderstorms per day In the afternoon and evening.
We were there Sep 21-27 2012! It was hot and humid most days, we had one evening rain. It was totally bearable. We had one day during the stay that we perfect 80 and breezy!!!