Here is a link to a website that can give you historical data for the specific dates that you are planning. Of course it can't predict the future but it is kind of neat to see the past range of temperatures. http://www.wunderground.com/tripplanner/index.asp
We have been to CTI 9x and we always go in September.... every year except 04 with Ivan hitting we had perfect weather... its may rain but only for 30 minutes or so and hell we are already in the pool... and its hot... i would say by 6:30AM its HOT.... I know crazy to be up that early on vacation.... 12 more days.... Sooooooooooooooon come!!