It depends on the hotel because I was told they are supposed to be heated all year round and no they weren't. I'd even read somewhere, can't remember where, it's been a few years now but that they were supposed to be always heated. From my experiences, stayed at Pop Century in Sep. 2012 and Aug. 2013. Hot temperatures during the day so the main pool and one of the other pools felt good and cool but at night when temps went down to the 70's, these same pools was still cold as earlier in the day and did not feel good at all. Never could enjoy the pools at night because of that. Went to Beach Club in May 2014 and May 2018. Stormalong Bay had the same problem. Both trips. Made me mad. I'll just say that all of this basically told me that the heating was a lie and that they kept them a good cold temperature no matter what. Made me wonder why these hotels never invested in having indoor pools as well. I've read of other Disney World fans that have wondered this also. Doesn't make any sense. Now then so I stayed at Grand Floridian, also in May 2018. Guess what? The main pool there was heated. And it felt glorious. Partially because during that trip, there was a lot of rain from a major storm system that deluged Florida which meant many cloudy days and temps only as high as in the 70's so Stormalong Bay on this same trip (it was a long split trip between BC and GF) was horrible unless it was sunny and hot but at GF, it was wonderful. So yes, it depends on the hotel and some of these places aren't heating their pools up from what they claim. I can also attest that if they are heated, you can see some steam rising as, well, what I witnessed at the GF pool but also heated pools in general and I stayed at BC again in January 2015. Very cool temperatures and one of the small pools and Stormalong Bay both, I could tell were not heated in the slightest. No steam at any time that I observed and also from my room, which the small pool I could see, a girl yelled loudly, "It's so cold! Oh my God!" and I went out to my balcony to observe and she was getting out, very frustrated. Didn't even bother swimming at any of them at that point. Also we all need to be wondering why they won't invest in building indoor pools at these hotels? A lot of fancy hotels do have both at their resorts and you'd think the "smart people" who work for Disney and the hotel corp. would have realized this a long time ago since DW is open all year round and Florida does still have cold nights and the occasional cold, hard freeze in the wintertime...as for me and my hubby, we are in the DVC and our ownership is at GF and Poly and we are in the process of selling as we have quit going to DW. Pains me to say it but this place has really gone downhill in everything and it's not worth the money anymore. Hopefully we will be able to sell our timeshares soon. What was once our happy place is sadly no more.