Pool swim season in Cape Girardeau, MO

When can you swim in an outdoor pool in Cape Girardeau, MO?

An unheated pool in Cape Girardeau reaches 78°F in Jul to Aug, about 2 months a year. The air allows up to 6 swimmable months with a heater (May to Oct).

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Heater options for a Cape Girardeau pool, side by side

For a 450 sq ft pool held at 80°F, at MO prices of 14.3¢/kWh electricity and $15/Mcf gas. All-in spreads the purchase over the equipment's life.

The cheapest way to the full season in Cape Girardeau

Solar panels + cover: 5 of 6 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 2 months here for about $50 a year (why a cover comes first). If you get quotes, ask for a heat pump sized to your pool's surface area; here it beats gas all-in (heat pump or gas).

Weather station: Cape Girardeau Municipal Airport, 5.9 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.

Cape Girardeau month by month: air, sun and pool water

Heating costs most in Oct (about $84 with a heat pump, $161 with gas). Sunshine peaks in Jun at 6.6 kWh/m²/day (NASA satellite data, 21.8 km grid cell). Highlighted months are swimmable with no heater.

How Cape Girardeau compares with nearby cities

Cape Girardeau ranks 26 of 80 Missouri cities for unheated swim months, and no nearby city gets a longer unheated season.