Pool swim season in Summerville, SC
Summerville, SC: how long the pool season really is
An unheated pool in Summerville reaches 78°F in Jul to Sep, about 3 months a year. The air allows up to 7 swimmable months with a heater (Apr to Oct).
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Heater options for a Summerville pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 3 | Jul to Sep | $0 | $0 |
| Solar cover only | 4 | Jun to Sep | $0 | $50 |
| Solar panels + cover | 6 | May to Oct | $0 | $283 |
| Heat pump + cover | 7 | Apr to Oct | $180 | $730 |
| Gas heater + cover | 7 | Apr to Oct | $382 | $807 |
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 Summerville
Solar panels + cover: 6 of 7 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 1 month 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: Summerville 4W, 3.7 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Summerville 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 | 58° | 46° | 2.9 | 48° | 54° | – | – |
| Feb | 62° | 49° | 3.5 | 48° | 54° | – | – |
| Mar | 69° | 55° | 4.5 | 54° | 60° | – | – |
| Apr | 76° | 63° | 5.8 | 62° | 68° | $116 | $239 |
| May | 82° | 71° | 6.2 | 70° | 76° | $35 | $81 |
| Jun | 87° | 77° | 6.4 | 77° | 83° | – | – |
| Jul | 90° | 81° | 6.2 | 82° | 88° | – | – |
| Aug | 90° | 80° | 5.6 | 83° | 89° | – | – |
| Sep | 85° | 75° | 4.8 | 79° | 85° | – | – |
| Oct | 77° | 65° | 4.0 | 71° | 77° | $29 | $62 |
| Nov | 68° | 55° | 3.1 | 60° | 66° | – | – |
| Dec | 61° | 49° | 2.6 | 52° | 58° | – | – |
Heating costs most in Apr (about $116 with a heat pump, $239 with gas). Sunshine peaks in Jun at 6.4 kWh/m²/day (NASA satellite data, 62.5 km grid cell). Highlighted months are swimmable with no heater.
How Summerville compares with nearby cities
Summerville ranks 24 of 42 South Carolina cities for unheated swim months; North Charleston, Goose Creek, Hanahan nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| North Charleston, SC | 9 mi | 4 | 8 | $257 |
| Goose Creek, SC | 10 mi | 4 | 8 | $257 |
| Hanahan, SC | 11 mi | 4 | 8 | $257 |
| Charleston, SC | 17 mi | 4 | 7 | $84 |
| Moncks Corner, SC | 17 mi | 4 | 7 | $111 |
| Mount Pleasant, SC | 23 mi | 4 | 7 | $124 |