Pool swim season in Washington, IN
Swim season in Washington without a heater, and with one
An unheated pool in Washington reaches 78°F in Jul to Aug, about 2 months a year. The air allows up to 5 swimmable months with a heater (May to Sep).
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Heater options for a Washington pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 2 | Jul to Aug | $0 | $0 |
| Solar cover only | 4 | Jun to Sep | $0 | $50 |
| Solar panels + cover | 5 | May to Sep | $0 | $283 |
| Heat pump + cover | 5 | May to Sep | $93 | $643 |
| Gas heater + cover | 5 | May to Sep | $128 | $553 |
For a 450 sq ft pool held at 80°F, at IN prices of 17.0¢/kWh electricity and $11/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Washington
Solar cover only: 4 of 5 possible months for about $50 a year all-in, which works out near $25 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: Washington 1 W, 2.2 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Washington 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 | 40° | 32° | 2.0 | 33° | 39° | – | – |
| Feb | 46° | 37° | 2.7 | 34° | 40° | – | – |
| Mar | 57° | 46° | 3.7 | 42° | 48° | – | – |
| Apr | 69° | 57° | 5.0 | 54° | 60° | – | – |
| May | 77° | 67° | 5.6 | 64° | 70° | $93 | $128 |
| Jun | 85° | 74° | 6.4 | 74° | 80° | – | – |
| Jul | 87° | 77° | 6.2 | 79° | 85° | – | – |
| Aug | 86° | 76° | 5.7 | 79° | 85° | – | – |
| Sep | 81° | 69° | 4.7 | 74° | 80° | – | – |
| Oct | 70° | 58° | 3.4 | 64° | 70° | – | – |
| Nov | 56° | 46° | 2.4 | 52° | 58° | – | – |
| Dec | 45° | 37° | 1.7 | 40° | 46° | – | – |
Heating costs most in May (about $93 with a heat pump, $128 with gas). Sunshine peaks in Jun at 6.4 kWh/m²/day (NASA satellite data, 34.4 km grid cell). Highlighted months are swimmable with no heater.
How Washington compares with nearby cities
Washington ranks 9 of 88 Indiana cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Vincennes, IN | 19 mi | 2 | 6 | $215 |
| Jasper, IN | 22 mi | 2 | 6 | $185 |
| Bedford, IN | 39 mi | 0 | 5 | $199 |
| Bloomington, IN | 49 mi | 0 | 5 | $179 |
| Evansville, IN | 51 mi | 2 | 6 | $136 |
| Terre Haute, IN | 57 mi | 2 | 6 | $215 |