Pool swim season in Germantown, WI
Germantown, WI: how long the pool season really is
An unheated pool in Germantown never reaches 78°F in a normal year. It peaks around 72°F in Aug. The air allows up to 4 swimmable months with a heater (Jun to Sep).
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Heater options for a Germantown pool, side by side
| 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 | 4 | Jun to Sep | $0 | $283 |
| Heat pump + cover | 4 | Jun to Sep | $264 | $814 |
| Gas heater + cover | 4 | Jun to Sep | $298 | $723 |
For a 450 sq ft pool held at 80°F, at WI prices of 19.1¢/kWh electricity and $11/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Germantown
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.
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: Germantown Wastewater Utility, 0.3 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Germantown 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° | 1.6 | 21° | 27° | – | – |
| Feb | 31° | 22° | 2.7 | 20° | 26° | – | – |
| Mar | 42° | 33° | 3.7 | 28° | 34° | – | – |
| Apr | 54° | 44° | 4.6 | 40° | 46° | – | – |
| May | 66° | 56° | 5.5 | 52° | 58° | – | – |
| Jun | 76° | 65° | 6.1 | 64° | 70° | $114 | $130 |
| Jul | 81° | 70° | 6.2 | 71° | 77° | $31 | $38 |
| Aug | 79° | 68° | 5.3 | 72° | 78° | $26 | $30 |
| Sep | 72° | 61° | 4.2 | 66° | 72° | $93 | $100 |
| Oct | 59° | 49° | 2.7 | 55° | 61° | – | – |
| Nov | 45° | 36° | 1.8 | 41° | 47° | – | – |
| Dec | 33° | 25° | 1.3 | 29° | 35° | – | – |
Heating costs most in Jun (about $114 with a heat pump, $130 with gas). Sunshine peaks in Jul at 6.2 kWh/m²/day (NASA satellite data, 42.3 km grid cell). Highlighted months are swimmable with no heater.
How Germantown compares with nearby cities
Germantown ranks 80 of 98 Wisconsin cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Menomonee Falls, WI | 5 mi | 0 | 4 | $264 |
| Richfield, WI | 5 mi | 0 | 4 | $202 |
| Mequon, WI | 6 mi | 0 | 4 | $264 |
| Cedarburg, WI | 8 mi | 0 | 4 | $213 |
| Lisbon, WI | 8 mi | 0 | 4 | $202 |
| Sussex, WI | 9 mi | 0 | 4 | $202 |