Pool swim season in Vernal, UT
Vernal, UT: how long the pool season really is
An unheated pool in Vernal never reaches 78°F in a normal year. It peaks around 75°F in Aug. The air allows up to 5 swimmable months with a heater (May to Sep).
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What each heater buys you in Vernal
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 0 | no month | $0 | $0 |
| Solar cover only | 2 | Jul to Aug | $0 | $50 |
| Solar panels + cover | 4 | Jun to Sep | $0 | $283 |
| Heat pump + cover | 5 | May to Sep | $270 | $820 |
| Gas heater + cover | 5 | May to Sep | $388 | $813 |
For a 450 sq ft pool held at 80°F, at UT prices of 13.2¢/kWh electricity and $10/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Vernal
Solar panels + cover: 4 of 5 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 2 months here for about $50 a year (why a cover comes first). If you get quotes, ask for gas as well as a heat pump: once the purchase price is counted, gas comes out cheaper all-in here (heat pump or gas).
Weather station: Vernal, 0.8 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Vernal 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 | 29° | 20° | 2.4 | 20° | 26° | – | – |
| Feb | 37° | 27° | 3.3 | 24° | 30° | – | – |
| Mar | 51° | 39° | 4.5 | 34° | 40° | – | – |
| Apr | 60° | 47° | 5.8 | 46° | 52° | – | – |
| May | 70° | 56° | 6.8 | 55° | 61° | $160 | $220 |
| Jun | 81° | 66° | 7.7 | 66° | 72° | $61 | $95 |
| Jul | 89° | 73° | 7.2 | 74° | 80° | $3 | $6 |
| Aug | 86° | 71° | 6.4 | 75° | 81° | – | – |
| Sep | 76° | 61° | 5.4 | 68° | 74° | $46 | $67 |
| Oct | 61° | 48° | 3.9 | 56° | 62° | – | – |
| Nov | 46° | 35° | 2.7 | 41° | 47° | – | – |
| Dec | 31° | 22° | 2.0 | 27° | 33° | – | – |
Heating costs most in May (about $160 with a heat pump, $220 with gas). Sunshine peaks in Jun at 7.7 kWh/m²/day (NASA satellite data, 6.3 km grid cell). Highlighted months are swimmable with no heater.
How Vernal compares with nearby cities
Vernal ranks 64 of 67 Utah cities for unheated swim months; Fruita, Grand Junction nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Green River, WY | 73 mi | 0 | 4 | $226 |
| Rock Springs, WY | 81 mi | 0 | 4 | $228 |
| Evanston, WY | 93 mi | 0 | 4 | $394 |
| Heber, UT | 97 mi | 0 | 5 | $381 |
| Fruita, CO | 99 mi | 2 | 5 | $175 |
| Grand Junction, CO | 107 mi | 2 | 5 | $115 |