I'll agree with all the previous posters with a couple of caveats. If you get cold easily (as I do) or you are planning on multiple dives, I'd go with the full protection of at least a 3mm. Typically, if I am doing a lot of dives, I will wear a 3mm shorty over a 3mm farmer jane. Even if you don't usually get cold your core temperature will drop when doing mulitple dives. Also, if you are diving the wrecks, you will be going deeper where the temperatures are not qute as balmy as the +/- 84-86 degree waters of July in the Keys. Perhaps the best thing to do is to pack few options, if you have room. Have fun diving!