Toward the end of September was bad. We heard that the beginning of September wasn't too bad. So I guess it depends on which part of the month you were there.
We were there right after Labor Day last year. I can't remember having any trouble with bees. (Beer on the other hand...)
I was there the third week of Nov and the pool bar in the Sexy pool the bees were crazy. A couple of people got stung alone with the bartenders.