We live in north Florida - how are y’all’s winters?

Hi, we live in Saint Augustine, we are planning a keys trip the beginning of January. Its super cold in st Augustine. I keep reading mixed reviews. Is it too cold to go in the water in marathon and go boating, snorkeling, scuba diving, and lobstering? It’s for my 30th birthday, so if it’ll be too cold in the water, then we will probably push it out. Thank you so much for any insight

Tried to post in keys group got it removed