When we first starting going to WDW all of our trips started the day after Labor Day. The crowds are lower because most people don't take their kids out of school that early in the school year. Yes, it was hot, but we didn't get any more rain that we have at other times. And one year we were in the Orlando area for 16 days during a drought and had only one quick late afternoon shower the entire time! Last year we bumped our Sept date up to October to avoid a hurricane. Well, guess when the hurricane hit last year? OCTOBER, on our check out day - wound up spending our DD time hold up in our room and costing us an extra day because we couldn't check out. You just never know what mother nature will throw at you - but indeed the crowds are lower and we liked September.