I asked this question of a Florida native and client. Here is her response:
It really depends, but there are definitely times in Dec & Jan when it’s warm enough for the pools. Just this past year we went to Wilderness Lodge in December and then to Port Orleans in January and February. My kids went in the pools each time, but I only went in in Feb because they wanted me to try the waterslide. I thought it was cold, but they didn’t. Of course, once they got out of the water and the wind blew they were cold. In the afternoon it can sometimes be in the 70s or even 80s, but the evenings can get chilly. However, the previous year we went to All Star in December and it was the coldest time we had ever been at Disney. FL had a very cold winter that year as did the rest of the country. So, it’s really hard to say. It can be nice & warm, but you never know.
Thanks Heather for helping!