Pool swim season in Irmo, SC

Irmo, SC: how long the pool season really is

An unheated pool in Irmo 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 Irmo

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 Irmo

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: Cedar Creek 2E, 10.5 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.

Irmo month by month: air, sun and pool water

Heating costs most in Apr (about $163 with a heat pump, $321 with gas). Sunshine peaks in Jun at 6.4 kWh/m²/day (NASA satellite data, 52.3 km grid cell). Highlighted months are swimmable with no heater.

How Irmo compares with nearby cities

Irmo ranks 39 of 42 South Carolina cities for unheated swim months; Lexington, West Columbia, Forest Acres nearby get a longer season without a heater.