78 to 82 is the swimming sweet spot

Most people feel best swimming in water between 78 and 82°F (26–28°C). That’s the range you’ll find at most hotels and community pools, and for good reason: it’s warm enough that you don’t gasp on entry, but cool enough that you actually cool off when you’re moving.

The exact number depends on what you’re doing. Lap swimming and competitive training run cooler — think 77 to 80°F — because hard exercise generates a ton of body heat, and a warmer pool turns training into a slog. On the flip side, kids, older adults, or anyone doing water aerobics want 84 to 88°F. And the shallow-water lounging set? They’ll happily swim in water that feels like a bath, around 90°F, but that’s basically a hot tub that doesn’t call itself one.

A couple of notes: below about 70°F, you can swim but you won’t enjoy it for long — that’s serious exercise or polar-bear-plunge territory. And if you’re constantly cold because the pool is heated to, say, 75°F, don’t push through it. Being cold is miserable and it makes muscles tighten up.