Pool swim season in North Charleston, SC
When can you swim in an outdoor pool in North Charleston, SC?
An unheated pool in North Charleston reaches 78°F in Jun to Sep, about 4 months a year. The air allows up to 8 swimmable months with a heater (Mar to Oct).
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Heater options for a North Charleston pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 4 | Jun to Sep | $0 | $0 |
| Solar cover only | 6 | May to Oct | $0 | $50 |
| Solar panels + cover | 7 | Apr to Oct | $0 | $283 |
| Heat pump + cover | 8 | Mar to Oct | $257 | $807 |
| Gas heater + cover | 8 | Mar to Oct | $521 | $946 |
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 North Charleston
Solar panels + cover: 7 of 8 possible months for about $283 a year all-in, which works out near $94 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: Charleston International Airport, 1.9 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
North Charleston month by month: air, sun and pool water
| Month | Air high | Air avg | Sun kWh/m²/day | Water, unheated | Water, covered | Heat pump $ | Gas $ |
|---|---|---|---|---|---|---|---|
| Jan | 60° | 50° | 3.0 | 51° | 57° | – | – |
| Feb | 64° | 53° | 3.6 | 52° | 58° | – | – |
| Mar | 70° | 59° | 4.8 | 58° | 64° | $166 | $324 |
| Apr | 77° | 66° | 6.1 | 65° | 71° | $79 | $170 |
| May | 84° | 73° | 6.5 | 73° | 79° | $8 | $18 |
| Jun | 89° | 79° | 6.5 | 80° | 86° | – | – |
| Jul | 91° | 83° | 6.4 | 84° | 90° | – | – |
| Aug | 90° | 81° | 5.7 | 85° | 91° | – | – |
| Sep | 85° | 77° | 4.9 | 81° | 87° | – | – |
| Oct | 78° | 68° | 4.2 | 74° | 80° | $4 | $9 |
| Nov | 69° | 58° | 3.3 | 63° | 69° | – | – |
| Dec | 63° | 52° | 2.6 | 55° | 61° | – | – |
Heating costs most in Mar (about $166 with a heat pump, $324 with gas). Sunshine peaks in May at 6.5 kWh/m²/day (NASA satellite data, 61.8 km grid cell). Highlighted months are swimmable with no heater.
How North Charleston compares with nearby cities
North Charleston ranks 10 of 42 South Carolina cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Hanahan, SC | 4 mi | 4 | 8 | $257 |
| Goose Creek, SC | 6 mi | 4 | 8 | $257 |
| Charleston, SC | 8 mi | 4 | 7 | $84 |
| Summerville, SC | 9 mi | 3 | 7 | $180 |
| Mount Pleasant, SC | 14 mi | 4 | 7 | $124 |
| James Island, SC | 15 mi | 4 | 7 | $84 |