Pool swim season in Sterling, CO
Sterling, CO: how long the pool season really is
An unheated pool in Sterling reaches 78°F in Aug, about 1 month a year. The air allows up to 5 swimmable months with a heater (May to Sep).
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What each heater buys you in Sterling
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 1 | Aug | $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 | $229 | $779 |
| Gas heater + cover | 5 | May to Sep | $294 | $719 |
For a 450 sq ft pool held at 80°F, at CO prices of 16.8¢/kWh electricity and $11/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Sterling
Solar panels + cover: 4 of 5 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 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: Sterling, 1 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Sterling 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 | 42° | 29° | 2.5 | 28° | 34° | – | – |
| Feb | 46° | 32° | 3.2 | 31° | 37° | – | – |
| Mar | 57° | 42° | 4.6 | 39° | 45° | – | – |
| Apr | 64° | 50° | 5.6 | 48° | 54° | – | – |
| May | 73° | 60° | 6.4 | 58° | 64° | $168 | $208 |
| Jun | 85° | 71° | 7.4 | 70° | 76° | $40 | $58 |
| Jul | 91° | 77° | 7.2 | 78° | 84° | – | – |
| Aug | 89° | 74° | 6.4 | 79° | 85° | – | – |
| Sep | 81° | 65° | 5.3 | 72° | 78° | $21 | $28 |
| Oct | 66° | 51° | 3.8 | 59° | 65° | – | – |
| Nov | 53° | 39° | 2.7 | 44° | 50° | – | – |
| Dec | 42° | 29° | 2.1 | 33° | 39° | – | – |
Heating costs most in May (about $168 with a heat pump, $208 with gas). Sunshine peaks in Jun at 7.4 kWh/m²/day (NASA satellite data, 29.2 km grid cell). Highlighted months are swimmable with no heater.
How Sterling compares with nearby cities
Sterling ranks 4 of 53 Colorado cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Fort Morgan, CO | 40 mi | 0 | 5 | $282 |
| Evans, CO | 84 mi | 0 | 5 | $232 |
| Greeley, CO | 84 mi | 0 | 5 | $232 |
| Severance, CO | 88 mi | 0 | 4 | $138 |
| Scottsbluff, NE | 90 mi | 0 | 4 | $93 |
| Windsor, CO | 91 mi | 0 | 4 | $138 |