Pool swim season in Durham, NC
When can you swim in an outdoor pool in Durham, NC?
An unheated pool in Durham reaches 78°F in Jul to Aug, about 2 months a year. The air allows up to 6 swimmable months with a heater (Apr to Sep).
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
What each heater buys you in Durham
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 2 | Jul to Aug | $0 | $0 |
| Solar cover only | 4 | Jun to Sep | $0 | $50 |
| Solar panels + cover | 5 | May to Sep | $0 | $283 |
| Heat pump + cover | 6 | Apr to Sep | $251 | $801 |
| Gas heater + cover | 6 | Apr to Sep | $523 | $948 |
For a 450 sq ft pool held at 80°F, at NC prices of 14.9¢/kWh electricity and $16/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Durham
Solar panels + cover: 5 of 6 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: Durham, 5.7 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Durham 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 | 49° | 38° | 2.6 | 40° | 46° | – | – |
| Feb | 53° | 41° | 3.3 | 40° | 46° | – | – |
| Mar | 61° | 49° | 4.3 | 47° | 53° | – | – |
| Apr | 70° | 58° | 5.5 | 56° | 62° | $170 | $341 |
| May | 77° | 66° | 6.1 | 65° | 71° | $76 | $169 |
| Jun | 83° | 74° | 6.4 | 73° | 79° | $5 | $13 |
| Jul | 87° | 78° | 6.2 | 79° | 85° | – | – |
| Aug | 85° | 76° | 5.5 | 79° | 85° | – | – |
| Sep | 79° | 70° | 4.6 | 75° | 81° | – | – |
| Oct | 70° | 59° | 3.7 | 65° | 71° | – | – |
| Nov | 60° | 49° | 2.9 | 54° | 60° | – | – |
| Dec | 52° | 42° | 2.3 | 45° | 51° | – | – |
Heating costs most in Apr (about $170 with a heat pump, $341 with gas). Sunshine peaks in Jun at 6.4 kWh/m²/day (NASA satellite data, 64.1 km grid cell). Highlighted months are swimmable with no heater.
How Durham compares with nearby cities
Durham ranks 78 of 91 North 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 |
|---|---|---|---|---|
| Chapel Hill, NC | 9 mi | 2 | 7 | $264 |
| Morrisville, NC | 10 mi | 2 | 7 | $244 |
| Carrboro, NC | 11 mi | 2 | 7 | $289 |
| Cary, NC | 14 mi | 2 | 7 | $279 |
| Apex, NC | 17 mi | 2 | 7 | $279 |
| Raleigh, NC | 18 mi | 2 | 7 | $247 |