I have been in Miami in February and it is NICE. Temps in the 80's etc.

Our humidity , albut high, is not noticable. Dress for January in Florida. Bring a windbreaker, jeans etc. It "might" be in the high 70's but no guarantees. The water will be about 47-49F at that time. You do not want to fall in it all that much. The air 1" off of the water is a similar temp. Add a 70 mph boat into the mix with no windshield and you get the idea.

We are used to it and we don't see a whole lot of bikinis... Think Lake Cumberland at AOTH time but no humidity and COLD water.

The whales like it tho