Pool swim season in Fairmont, MN
Fairmont, MN: how long the pool season really is
An unheated pool in Fairmont never reaches 78°F in a normal year. It peaks around 75°F in Jul. The air allows up to 4 swimmable months with a heater (Jun to Sep).
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
What each heater buys you in Fairmont
| 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 | 4 | Jun to Sep | $111 | $661 |
| Gas heater + cover | 4 | Jun to Sep | $152 | $577 |
For a 450 sq ft pool held at 80°F, at MN prices of 16.4¢/kWh electricity and $11/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Fairmont
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 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: Fairmont, 0.1 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Fairmont 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 | 24° | 15° | 1.9 | 17° | 23° | – | – |
| Feb | 28° | 19° | 3.0 | 17° | 23° | – | – |
| Mar | 41° | 32° | 3.8 | 26° | 32° | – | – |
| Apr | 56° | 46° | 4.8 | 40° | 46° | – | – |
| May | 69° | 59° | 5.5 | 55° | 61° | – | – |
| Jun | 80° | 70° | 6.1 | 68° | 74° | $58 | $82 |
| Jul | 83° | 73° | 6.5 | 75° | 81° | – | – |
| Aug | 81° | 71° | 5.5 | 75° | 81° | – | – |
| Sep | 75° | 63° | 4.3 | 69° | 75° | $53 | $70 |
| Oct | 60° | 50° | 2.9 | 56° | 62° | – | – |
| Nov | 43° | 34° | 2.0 | 41° | 47° | – | – |
| Dec | 29° | 21° | 1.5 | 26° | 32° | – | – |
Heating costs most in Jun (about $58 with a heat pump, $82 with gas). Sunshine peaks in Jul at 6.5 kWh/m²/day (NASA satellite data, 16.4 km grid cell). Highlighted months are swimmable with no heater.
How Fairmont compares with nearby cities
Fairmont ranks 6 of 103 Minnesota cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| North Mankato, MN | 43 mi | 0 | 4 | $154 |
| Mankato, MN | 44 mi | 0 | 4 | $156 |
| New Ulm, MN | 46 mi | 0 | 4 | $134 |
| Spencer, IA | 49 mi | 0 | 4 | $111 |
| St. Peter, MN | 53 mi | 0 | 4 | $185 |
| Albert Lea, MN | 55 mi | 0 | 4 | $143 |