What is the perfect temperature for a backyard pool?

83°F is the sweet spot for general swimming, lounging, and cannonballs. Any warmer feels like soup, any cooler makes people whine. Lap swimmers prefer 78-80°F, therapy pools like 86-88°F, but for normal hosting, set it at 83°F and forget it. Don’t go over 85°F unless you want bathwater nobody moves in.