I have lived in Jacksonville Beach for most of my life and people often ask me what our winters are like here. I tell them that the only really cold month is February but if I had to be totally honest... I've walked on the beach with shorts on during that month in the past. What I'm trying to say is, that it's really unpredictable. The only thing that is a constant is the fact that no matter what the temperature, it varies from week to week. Sometimes, day to day.
Our golf courses rarely close unless there is a frost and by mid-morning that has melted and they generally open up at that time.
One thing for sure, there is always someone on the beach... no matter the weather. Many Floridians love the change of temperature and simply layer up and head out for a walk.
If you choose to stay in my beach rental in the winter, my balconies face west so, even if there is a brisk breeze on the beach, you can always sit on the balcony and get your tan!