I really think this quesiton depends on where you are coming from and what you are used to. We are from Texas and we like our water warm. The pools are heated but not nearly warm enough for our blood! We went last Nov/Dec and tried to swim. It was pretty warm out but a bit later in the day and we found it far too cold for us. But, there were tons of people swimming! If your kids are die hard swimming fans and the weather holds out, they could swim for sure. If they don't want to be too cold, might want to stick to the hot tub.