Pool swim season in St. George, UT
St. George, UT: how long the pool season really is
An unheated pool in St. George reaches 78°F in Jun to Sep, about 4 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 St. George pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 4 | Jun 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 | $160 | $710 |
| Gas heater + cover | 7 | Apr to Oct | $240 | $665 |
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 St. George
Solar panels + cover: 6 of 7 possible months for about $283 a year all-in, which works out near $142 for each month it adds.
A solar cover alone adds no swim months here, so if you want a longer season you need a heater (why); still use one at night to hold the heat you pay for. 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: St George, 3.3 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
St. George 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 | 54° | 41° | 2.8 | 41° | 47° | – | – |
| Feb | 59° | 46° | 3.7 | 44° | 50° | – | – |
| Mar | 68° | 53° | 5.2 | 52° | 58° | – | – |
| Apr | 75° | 60° | 6.5 | 60° | 66° | $110 | $160 |
| May | 85° | 71° | 7.6 | 70° | 76° | $28 | $47 |
| Jun | 96° | 80° | 8.4 | 81° | 87° | – | – |
| Jul | 102° | 87° | 7.5 | 88° | 94° | – | – |
| Aug | 100° | 85° | 7.0 | 90° | 96° | – | – |
| Sep | 92° | 77° | 6.0 | 84° | 90° | – | – |
| Oct | 79° | 63° | 4.5 | 71° | 77° | $22 | $33 |
| Nov | 64° | 49° | 3.2 | 56° | 62° | – | – |
| Dec | 53° | 40° | 2.4 | 44° | 50° | – | – |
Heating costs most in Apr (about $110 with a heat pump, $160 with gas). Sunshine peaks in Jun at 8.4 kWh/m²/day (NASA satellite data, 47.5 km grid cell). Highlighted months are swimmable with no heater.
How St. George compares with nearby cities
St. George ranks 1 of 67 Utah cities for unheated swim months; North Las Vegas nearby gets a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Washington, UT | 6 mi | 4 | 7 | $160 |
| Ivins, UT | 9 mi | 4 | 7 | $160 |
| Hurricane, UT | 13 mi | 3 | 7 | $209 |
| Mesquite, NV | 35 mi | 4 | 8 | $253 |
| Cedar City, UT | 50 mi | 0 | 5 | $209 |
| North Las Vegas, NV | 100 mi | 5 | 8 | $162 |