In south Florida the bulk of the tourist season is from Jan. to April. Road traffic can be awful then. That tends to be when the weather is best though. From time to time a cold front will pass over the area. It can be quite chilly for a few days when that happens, but winter like weather tends to only last a few hours in the day as the afternoons will be nice and sunny typically.
My favorite month here in SW Florida is April. The weather isn't to hot then typically, humidity levels are decent. The cold fronts have all but stopped by then, and some of the northern tourists have returned home making it easier to get around.