Pool swim season in Yakima, WA
When can you swim in an outdoor pool in Yakima, WA?
An unheated pool in Yakima never reaches 78°F in a normal year. It peaks around 77°F in Aug. The air allows up to 5 swimmable months with a heater (May to Sep).
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Heater options for a Yakima pool, side by side
| 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 | $205 | $755 |
| Gas heater + cover | 5 | May to Sep | $487 | $912 |
For a 450 sq ft pool held at 80°F, at WA prices of 14.4¢/kWh electricity and $18/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Yakima
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 a heat pump sized to your pool's surface area; here it beats gas all-in (heat pump or gas).
Weather station: Yakima #2, 0.9 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Yakima 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° | 33° | 1.3 | 31° | 37° | – | – |
| Feb | 48° | 39° | 2.3 | 36° | 42° | – | – |
| Mar | 57° | 46° | 3.4 | 43° | 49° | – | – |
| Apr | 65° | 53° | 5.0 | 51° | 57° | – | – |
| May | 74° | 61° | 6.0 | 60° | 66° | $127 | $293 |
| Jun | 80° | 67° | 6.8 | 68° | 74° | $53 | $132 |
| Jul | 88° | 74° | 7.5 | 75° | 81° | – | – |
| Aug | 88° | 73° | 6.3 | 77° | 83° | – | – |
| Sep | 79° | 65° | 4.6 | 71° | 77° | $25 | $62 |
| Oct | 64° | 52° | 2.8 | 59° | 65° | – | – |
| Nov | 49° | 40° | 1.5 | 45° | 51° | – | – |
| Dec | 38° | 32° | 1.0 | 34° | 40° | – | – |
Heating costs most in May (about $127 with a heat pump, $293 with gas). Sunshine peaks in Jul at 7.5 kWh/m²/day (NASA satellite data, 10.8 km grid cell). Highlighted months are swimmable with no heater.
How Yakima compares with nearby cities
Yakima ranks 8 of 91 Washington cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Ellensburg, WA | 28 mi | 0 | 4 | $235 |
| Sunnyside, WA | 32 mi | 0 | 5 | $312 |
| Grandview, WA | 39 mi | 0 | 5 | $301 |
| East Wenatchee, WA | 58 mi | 0 | 5 | $200 |
| West Richland, WA | 59 mi | 0 | 5 | $187 |
| Wenatchee, WA | 59 mi | 0 | 5 | $200 |