Hey there, Sharon! Let's dive in to the sparkling Walt Disney World Resort pools!
I absolutely adore Disney's Caribbean Beach Resort, with its island-getaway feel. The Fuentes del Morro pool is one of best there is, and, like all Walt Disney World pools, it is heated to a comfortable 82 degrees year-round.
Your next question - is it warm enough to swim? - depends on the air temperature and your own cold tolerance. As a Texan, I'm guessing your blood is as thin as this Florida girl's is. While I've seen lots of warm December days here in my home state, it can also get quite chilly on occasion. My best advice to you is to watch the forecast for the week before your visit. If the temps are going to be in the 70s or 80s, you'll probably be ok to take a dip. Anything lower is too low for my blood.
Also, if you hit the pool at mid-day when the sun is at its height, you're more likely to have a warmer swim.
I hope this helps you dive into your vacation planning, Sharon. Come on by and see us again if you have any more questions!
Keep Disney Dreaming,
Kathy K.