I live here in Central Florida and have visited the Parks all times of the year, Do NOT, I repeat, DO NOT come down here in August unless that is the ONLY time you can come. The heat and the humidity are almost unbearable and if next year is like this year, it will rain at some point almost every day. Just my opinion. June on the other hand is really pretty pleasant. I'd pick that month.
Hope this helps!
Cindy