I did all my flight training at Pan Am Fort Pierce. The heat wasn't really an issue, yes it's hot in the summer on the ramp, but once you take off and get some altitude it cools off. Practicing touch-and-goes you will sweat though, as it isn't much cooler at traffic pattern altitude.
The thunderstorms in Florida are usually pretty small, one cell storms that you can fly around. Not a big deal, unless you're IFR then you just have to make sure ATC doesn't vector you into one. In the summer,
every day between 2:00 PM till about 6:00 PM you will get thunderstorms. Although they do occur at any time during the day. I almost never cancelled a local flight, and only a few cross countries due to lines of t-storms blocking the route.
Hurricanes are another issue all together. In 2004 Fort Pierce took a direct hit by 2 hurricanes only a month apart. I was a CFI and the school closed for 2 months for repairs. Last year 2005, South Florida got direct hits from 2 hurricanes. Katrina & Wilma. While they didn't hit Fort Pierce, I think they still disrupted flight training.
FPR is a good training airport, with VRB right next door, and good instrument approaches at both airports. The normal weather you can deal with. Hurricanes appear to be increasing in frequency, but you can't predict where they will go.
