I think all Disney pools are heated. We have always been lucky to at least be able to swim once on our trips, even if it was December or Feb. We swam twice at SSR in Feb. We always look at the 5 day forecast and pick the warmest afternoon (it has to be at least 72, or I won't even consider it)I'm a
Southerner and my tolerance for air temps is pretty weak!

I remember one time on December stay at CBR (preDVC), the day we arrived it was 75 and that appeared to be the warmest it was going to be all week. We checked in, unloaded, and promptly changed in to our suits and hit the pool. Good thing, because we never had another opportunity the whole week that we were there. Swimming is a big deal to my kids, so we check the forecast and plan the rest of the trip around swim day! I just have to say, that I don't envy you trying to keep up with your large family at SAB. It about drove me nuts with my 3 kids! We just had to travel around from one section to the next as a family. Have a great trip!