Pool swim season in Winona, MN
Swim season in Winona without a heater, and with one
An unheated pool in Winona never reaches 78°F in a normal year. It peaks around 76°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 Winona
| 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 | $247 | $797 |
| Gas heater + cover | 5 | May to Sep | $324 | $749 |
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 Winona
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: Winona, 1.7 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Winona 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 | 27° | 19° | 1.8 | 21° | 27° | – | – |
| Feb | 32° | 24° | 2.9 | 21° | 27° | – | – |
| Mar | 45° | 35° | 4.0 | 31° | 37° | – | – |
| Apr | 59° | 49° | 4.6 | 44° | 50° | – | – |
| May | 72° | 61° | 5.5 | 58° | 64° | $163 | $207 |
| Jun | 80° | 70° | 6.0 | 69° | 75° | $45 | $65 |
| Jul | 85° | 75° | 6.3 | 76° | 82° | – | – |
| Aug | 82° | 73° | 5.3 | 76° | 82° | – | – |
| Sep | 75° | 65° | 4.1 | 70° | 76° | $39 | $52 |
| Oct | 61° | 52° | 2.7 | 58° | 64° | – | – |
| Nov | 45° | 37° | 1.7 | 43° | 49° | – | – |
| Dec | 32° | 25° | 1.3 | 30° | 36° | – | – |
Heating costs most in May (about $163 with a heat pump, $207 with gas). Sunshine peaks in Jul at 6.3 kWh/m²/day (NASA satellite data, 51.7 km grid cell). Highlighted months are swimmable with no heater.
How Winona compares with nearby cities
Winona ranks 1 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 |
|---|---|---|---|---|
| Holmen, WI | 21 mi | 0 | 5 | $286 |
| Onalaska, WI | 26 mi | 0 | 5 | $286 |
| La Crosse, WI | 27 mi | 0 | 4 | $218 |
| Rochester, MN | 40 mi | 0 | 4 | $195 |
| Eau Claire, WI | 54 mi | 0 | 4 | $167 |
| Red Wing, MN | 59 mi | 0 | 4 | $144 |