Pool swim season in Pasco, WA
When can you swim in an outdoor pool in Pasco, WA?
An unheated pool in Pasco 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 Pasco 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 | $190 | $740 |
| Gas heater + cover | 5 | May to Sep | $454 | $879 |
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 Pasco
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: Pasco Tri Cities Airport, 0.3 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Pasco 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 | 41° | 35° | 1.2 | 33° | 39° | – | – |
| Feb | 49° | 38° | 2.3 | 36° | 42° | – | – |
| Mar | 59° | 46° | 3.6 | 43° | 49° | – | – |
| Apr | 67° | 53° | 5.4 | 52° | 58° | – | – |
| May | 77° | 61° | 6.5 | 61° | 67° | $118 | $275 |
| Jun | 83° | 68° | 7.2 | 69° | 75° | $42 | $106 |
| Jul | 93° | 75° | 7.7 | 76° | 82° | – | – |
| Aug | 91° | 73° | 6.4 | 77° | 83° | – | – |
| Sep | 81° | 64° | 4.7 | 70° | 76° | $30 | $73 |
| Oct | 66° | 52° | 3.0 | 58° | 64° | – | – |
| Nov | 50° | 41° | 1.6 | 45° | 51° | – | – |
| Dec | 41° | 34° | 1.0 | 36° | 42° | – | – |
Heating costs most in May (about $118 with a heat pump, $275 with gas). Sunshine peaks in Jul at 7.7 kWh/m²/day (NASA satellite data, 39.0 km grid cell). Highlighted months are swimmable with no heater.
How Pasco compares with nearby cities
Pasco ranks 7 of 91 Washington cities for unheated swim months; Kennewick, Hermiston, Walla Walla nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Kennewick, WA | 5 mi | 1 | 5 | $141 |
| Richland, WA | 8 mi | 0 | 5 | $187 |
| West Richland, WA | 13 mi | 0 | 5 | $187 |
| Hermiston, OR | 31 mi | 1 | 5 | $202 |
| Grandview, WA | 38 mi | 0 | 5 | $301 |
| Walla Walla, WA | 40 mi | 1 | 5 | $187 |