Pool swim season in Marquette, MI
Marquette, MI: how long the pool season really is
An unheated pool in Marquette never reaches 78°F in a normal year. It peaks around 68°F in Aug. The air allows up to 2 swimmable months with a heater (Jul to Aug).
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What each heater buys you in Marquette
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 0 | no month | $0 | $0 |
| Solar cover only | 0 | no month | $0 | $50 |
| Solar panels + cover | 2 | Jul to Aug | $0 | $283 |
| Heat pump + cover | 2 | Jul to Aug | $175 | $725 |
| Gas heater + cover | 2 | Jul to Aug | $179 | $604 |
For a 450 sq ft pool held at 80°F, at MI prices of 21.7¢/kWh electricity and $11/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Marquette
Solar panels + cover: 2 of 2 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: Marquette, 0.9 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Marquette 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 | 25° | 19° | 1.1 | 20° | 26° | – | – |
| Feb | 27° | 20° | 1.9 | 18° | 24° | – | – |
| Mar | 35° | 28° | 3.2 | 24° | 30° | – | – |
| Apr | 46° | 38° | 4.4 | 35° | 41° | – | – |
| May | 59° | 50° | 5.4 | 47° | 53° | – | – |
| Jun | 68° | 59° | 5.9 | 57° | 63° | – | – |
| Jul | 75° | 66° | 6.0 | 66° | 72° | $104 | $106 |
| Aug | 74° | 66° | 5.0 | 68° | 74° | $71 | $73 |
| Sep | 67° | 59° | 3.7 | 64° | 70° | – | – |
| Oct | 54° | 47° | 2.2 | 52° | 58° | – | – |
| Nov | 41° | 35° | 1.2 | 39° | 45° | – | – |
| Dec | 30° | 24° | 0.9 | 27° | 33° | – | – |
Heating costs most in Jul (about $104 with a heat pump, $106 with gas). Sunshine peaks in Jul at 6.0 kWh/m²/day (NASA satellite data, 9.8 km grid cell). Highlighted months are swimmable with no heater.
How Marquette compares with nearby cities
Marquette ranks 88 of 90 Michigan cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Escanaba, MI | 58 mi | 0 | 3 | $366 |
| Marinette, WI | 102 mi | 0 | 4 | $288 |
| Suamico, WI | 136 mi | 0 | 4 | $293 |
| Howard, WI | 141 mi | 0 | 4 | $293 |
| Green Bay, WI | 143 mi | 0 | 4 | $298 |
| Sault Ste. Marie, MI | 144 mi | 0 | 3 | $359 |