I'm not Webray, but hurricane season is technically June 1-Nov 30, so the threat is always there. Hurricane Charlie hit the area on August 13 last year. I would not let that deter me, but just keep it in mind.
Thunderstorms are pretty much a daily thing that time of year. They usually roll by quickly, but don't necessarily cool things off. The evenings are humid, so dress accordingly. The air can be exceptionally sticky.
The crowds are thinner because of school reopenings. Labor Day is probably the least crowded summer holiday.....this year it will possibly be more crowded than traditionally because of the anniversary.