Pool swim season in Stillwater, OK
Swim season in Stillwater without a heater, and with one
An unheated pool in Stillwater 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).
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Heater options for a Stillwater 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 | $246 | $796 |
| Gas heater + cover | 7 | Apr to Oct | $490 | $915 |
For a 450 sq ft pool held at 80°F, at OK prices of 13.8¢/kWh electricity and $14/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Stillwater
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: Stillwater 2 W, 1.3 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Stillwater 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° | 37° | 2.7 | 38° | 44° | – | – |
| Feb | 54° | 42° | 3.4 | 40° | 46° | – | – |
| Mar | 63° | 51° | 4.4 | 48° | 54° | – | – |
| Apr | 72° | 60° | 5.5 | 58° | 64° | $141 | $272 |
| May | 79° | 69° | 6.1 | 67° | 73° | $53 | $115 |
| Jun | 88° | 78° | 7.0 | 77° | 83° | – | – |
| Jul | 94° | 83° | 6.9 | 84° | 90° | – | – |
| Aug | 93° | 81° | 6.1 | 85° | 91° | – | – |
| Sep | 85° | 73° | 5.1 | 79° | 85° | – | – |
| Oct | 73° | 61° | 3.9 | 68° | 74° | $52 | $103 |
| Nov | 61° | 49° | 2.9 | 55° | 61° | – | – |
| Dec | 51° | 40° | 2.3 | 44° | 50° | – | – |
Heating costs most in Apr (about $141 with a heat pump, $272 with gas). Sunshine peaks in Jun at 7.0 kWh/m²/day (NASA satellite data, 56.0 km grid cell). Highlighted months are swimmable with no heater.
How Stillwater compares with nearby cities
Stillwater ranks 22 of 45 Oklahoma cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Guthrie, OK | 26 mi | 3 | 7 | $225 |
| Edmond, OK | 37 mi | 3 | 7 | $258 |
| Ponca City, OK | 41 mi | 3 | 7 | $266 |
| Choctaw, OK | 46 mi | 3 | 7 | $225 |
| Enid, OK | 48 mi | 3 | 7 | $266 |
| Midwest City, OK | 49 mi | 3 | 7 | $225 |