Pool swim season in Port Royal, SC
Swim season in Port Royal without a heater, and with one
An unheated pool in Port Royal reaches 78°F in Jun to Sep, about 4 months a year. The air allows up to 9 swimmable months with a heater (Mar to Nov).
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What each heater buys you in Port Royal
| 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 | 9 | Mar to Nov | $296 | $846 |
| Gas heater + cover | 9 | Mar to Nov | $606 | $1,031 |
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 Port Royal
Heat pump + cover: 9 of 9 possible months for about $846 a year all-in, which works out near $169 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: Beaufort Water Treatment Plant, 2.8 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Port Royal 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 | 61° | 51° | 3.0 | 52° | 58° | – | – |
| Feb | 65° | 54° | 3.6 | 53° | 59° | – | – |
| Mar | 72° | 60° | 4.8 | 59° | 65° | $147 | $294 |
| Apr | 77° | 67° | 6.1 | 67° | 73° | $65 | $143 |
| May | 84° | 75° | 6.5 | 74° | 80° | – | – |
| Jun | 89° | 80° | 6.5 | 81° | 87° | – | – |
| Jul | 91° | 83° | 6.4 | 85° | 91° | – | – |
| Aug | 90° | 82° | 5.7 | 85° | 91° | – | – |
| Sep | 86° | 78° | 4.9 | 82° | 88° | – | – |
| Oct | 79° | 70° | 4.2 | 75° | 81° | – | – |
| Nov | 70° | 60° | 3.3 | 65° | 71° | $84 | $169 |
| Dec | 62° | 53° | 2.6 | 56° | 62° | – | – |
Heating costs most in Mar (about $147 with a heat pump, $294 with gas). Sunshine peaks in May at 6.5 kWh/m²/day (NASA satellite data, 24.7 km grid cell). Highlighted months are swimmable with no heater.
How Port Royal compares with nearby cities
Port Royal ranks 5 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 |
|---|---|---|---|---|
| Beaufort, SC | 7 mi | 4 | 7 | $73 |
| Hilton Head Island, SC | 12 mi | 4 | 9 | $296 |
| Bluffton, SC | 17 mi | 4 | 9 | $316 |
| Hardeeville, SC | 20 mi | 4 | 9 | $321 |
| Rincon, GA | 32 mi | 4 | 9 | $312 |
| Port Wentworth, GA | 32 mi | 4 | 9 | $312 |