First, there is no way to predict the weather in December; it is all over the map. Also, Florida is part of the Atlantic, not the Caribbean, where you could nail down a general daily temperature for the entire month.
I have been the week after Thanksgiving almost every year since 2000 and the weather is never the same year to year. The best thing you can do is watch the weather two days before you leave, pack accordingly and then decide if it is worth the walk from the pool to the room at that temperature. The pools are heated; the walk back to the room will not be.
Ultimately, only you can decide if you can tolerate the temperature; it is a very subjective question. I work outside and can tolerate the cold; also I live in the mid-Atlantic, so even if it was in the 60's in Florida, it would feel better than what was at home.