Oh, so you don't have a real winter... just a bit of slightly cooler weather...
I know, I know. However - it occasionally gets frosty - my main concern is gelcoat. While in general in excellent shape (for 36 years old anyway) it does have cracks here and there - they are all tiny, but let the water get in there and freeze a few times, and it will be a much bigger problem. So - gotta cover anyway.
I am sure people up north have much more serious potential problems - I almost feel ashamed butting into this discussion