Pool swim season in Green River, WY
Green River, WY: how long the pool season really is
An unheated pool in Green River never reaches 78°F in a normal year. It peaks around 72°F in Aug. The air allows up to 4 swimmable months with a heater (Jun to Sep).
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Heater options for a Green River pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 0 | no month | $0 | $0 |
| Solar cover only | 1 | Aug | $0 | $50 |
| Solar panels + cover | 4 | Jun to Sep | $0 | $283 |
| Heat pump + cover | 4 | Jun to Sep | $226 | $776 |
| Gas heater + cover | 4 | Jun to Sep | $364 | $789 |
For a 450 sq ft pool held at 80°F, at WY prices of 14.0¢/kWh electricity and $12/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Green River
Solar panels + cover: 4 of 4 possible months for about $283 a year all-in, which works out near $71 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: Green Rvr, 0.3 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Green River 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 | 31° | 20° | 2.2 | 20° | 26° | – | – |
| Feb | 36° | 25° | 3.1 | 22° | 28° | – | – |
| Mar | 47° | 35° | 4.4 | 31° | 37° | – | – |
| Apr | 56° | 43° | 5.7 | 42° | 48° | – | – |
| May | 66° | 52° | 6.7 | 51° | 57° | – | – |
| Jun | 78° | 62° | 7.6 | 62° | 68° | $106 | $170 |
| Jul | 87° | 70° | 7.3 | 70° | 76° | $30 | $54 |
| Aug | 85° | 68° | 6.4 | 72° | 78° | $14 | $24 |
| Sep | 76° | 58° | 5.3 | 65° | 71° | $76 | $116 |
| Oct | 61° | 46° | 3.8 | 53° | 59° | – | – |
| Nov | 44° | 31° | 2.5 | 38° | 44° | – | – |
| Dec | 32° | 21° | 1.8 | 25° | 31° | – | – |
Heating costs most in Jun (about $106 with a heat pump, $170 with gas). Sunshine peaks in Jun at 7.6 kWh/m²/day (NASA satellite data, 2.8 km grid cell). Highlighted months are swimmable with no heater.
How Green River compares with nearby cities
Green River ranks 6 of 11 Wyoming cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Rock Springs, WY | 14 mi | 0 | 4 | $228 |
| Vernal, UT | 73 mi | 0 | 5 | $270 |
| Evanston, WY | 79 mi | 0 | 4 | $394 |
| Riverton, WY | 118 mi | 0 | 4 | $182 |
| Heber, UT | 120 mi | 0 | 5 | $381 |
| North Logan, UT | 122 mi | 0 | 4 | $98 |