Pool swim season in Moses Lake, WA
Swim season in Moses Lake without a heater, and with one
An unheated pool in Moses Lake never reaches 78°F in a normal year. It peaks around 76°F in Aug. The air allows up to 5 swimmable months with a heater (May to Sep).
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Heater options for a Moses Lake 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 | $241 | $791 |
| Gas heater + cover | 5 | May to Sep | $566 | $991 |
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 Moses Lake
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: Moses Lake Grant County Airport, 4.9 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Moses Lake 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 | 36° | 30° | 1.1 | 28° | 34° | – | – |
| Feb | 44° | 35° | 2.2 | 32° | 38° | – | – |
| Mar | 55° | 43° | 3.5 | 40° | 46° | – | – |
| Apr | 64° | 51° | 5.2 | 49° | 55° | – | – |
| May | 74° | 60° | 6.4 | 58° | 64° | $140 | $319 |
| Jun | 80° | 66° | 7.0 | 67° | 73° | $59 | $147 |
| Jul | 90° | 73° | 7.5 | 74° | 80° | – | – |
| Aug | 88° | 72° | 6.3 | 76° | 82° | – | – |
| Sep | 79° | 63° | 4.6 | 69° | 75° | $42 | $100 |
| Oct | 63° | 50° | 2.9 | 56° | 62° | – | – |
| Nov | 46° | 38° | 1.5 | 42° | 48° | – | – |
| Dec | 36° | 30° | 0.9 | 32° | 38° | – | – |
Heating costs most in May (about $140 with a heat pump, $319 with gas). Sunshine peaks in Jul at 7.5 kWh/m²/day (NASA satellite data, 44.7 km grid cell). Highlighted months are swimmable with no heater.
How Moses Lake compares with nearby cities
Moses Lake ranks 9 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 |
|---|---|---|---|---|
| East Wenatchee, WA | 51 mi | 0 | 5 | $200 |
| Wenatchee, WA | 54 mi | 0 | 5 | $200 |
| West Richland, WA | 56 mi | 0 | 5 | $187 |
| Richland, WA | 58 mi | 0 | 5 | $187 |
| Pasco, WA | 60 mi | 0 | 5 | $190 |
| Ellensburg, WA | 61 mi | 0 | 4 | $235 |