Pool swim season in Fort Mill, SC

When can you swim in an outdoor pool in Fort Mill, SC?

An unheated pool in Fort Mill reaches 78°F in Jul to Aug, about 2 months a year. The air allows up to 7 swimmable months with a heater (Apr to Oct).

1. J
2. F
3. M
4. A
5. M
6. J
7. J
8. A
9. S
10. O
11. N
12. D

What each heater buys you in Fort Mill

For a 450 sq ft pool held at 80°F, at SC prices of 15.9¢/kWh electricity and $17/Mcf gas. All-in spreads the purchase over the equipment's life.

The cheapest way to the full season in Fort Mill

Solar panels + cover: 6 of 7 possible months for about $283 a year all-in, which works out near $71 for each month it adds.

Before you pay for any heater, buy a solar cover: on its own it adds 2 months here for about $50 a year (why a cover comes first). If you get quotes, ask for a heat pump sized to your pool's surface area; here it beats gas all-in (heat pump or gas).

Weather station: Rock Hill York County Airport, 6.8 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.

Fort Mill month by month: air, sun and pool water

Heating costs most in Apr (about $146 with a heat pump, $293 with gas). Sunshine peaks in Jun at 6.5 kWh/m²/day (NASA satellite data, 67.9 km grid cell). Highlighted months are swimmable with no heater.

How Fort Mill compares with nearby cities

Fort Mill ranks 32 of 42 South Carolina cities for unheated swim months, and no nearby city gets a longer unheated season.