I'm going to answer this one the best I can.
What part of the Gulf? If you are in the panhandle of Florida, you MIGHT get away with a wetsuit and a spry top on the warmest days. If you are further down, say St. Pete or so, probably just a shorty wetsuit.
It's way to cold here where I'm at during that time of year AND the Corps of Engineers lets a lot of water out of the lakes, so I won't be doing any sailing until March at the earliest, and that's being optimistic.
I'm sure someone will be able to answer better than I though.
Mike