Well I just got a house with solar already set up (so I don’t have a lot of experience with it) but yesterday, the solar heated it from 74 degrees in the morning (it cooled down during the cold spell, and I also turned off the solar for a couple of days as a test) to 82 degrees in one day. This is a 5 ft deep around 15,000 gallon pool. Before I turned it off, it had gotten to 88 degrees on May 1st and was evaporating water like crazy and was starting to grow some serious algae. I’d guess it’ll be near 86-88 tonight with a day like today.
In the townhouse complex we used to live in, the solar didn’t have a regulator, so it’d hit the 90s by July and stay there until September.