Pool swim season in Grants Pass, OR
Grants Pass, OR: how long the pool season really is
An unheated pool in Grants Pass 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 Grants Pass 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 | $217 | $767 |
| Gas heater + cover | 5 | May to Sep | $454 | $879 |
For a 450 sq ft pool held at 80°F, at OR prices of 15.5¢/kWh electricity and $17/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Grants Pass
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: Grants Pass, 0.8 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Grants Pass 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 | 48° | 42° | 1.7 | 40° | 46° | – | – |
| Feb | 54° | 45° | 2.6 | 43° | 49° | – | – |
| Mar | 60° | 48° | 3.6 | 47° | 53° | – | – |
| Apr | 65° | 53° | 5.0 | 52° | 58° | – | – |
| May | 74° | 60° | 6.4 | 60° | 66° | $137 | $278 |
| Jun | 81° | 66° | 7.4 | 67° | 73° | $59 | $130 |
| Jul | 91° | 73° | 7.9 | 75° | 81° | – | – |
| Aug | 91° | 73° | 6.8 | 77° | 83° | – | – |
| Sep | 84° | 66° | 5.2 | 72° | 78° | $21 | $46 |
| Oct | 70° | 56° | 3.4 | 61° | 67° | – | – |
| Nov | 54° | 46° | 1.9 | 50° | 56° | – | – |
| Dec | 46° | 40° | 1.4 | 42° | 48° | – | – |
Heating costs most in May (about $137 with a heat pump, $278 with gas). Sunshine peaks in Jul at 7.9 kWh/m²/day (NASA satellite data, 15.7 km grid cell). Highlighted months are swimmable with no heater.
How Grants Pass compares with nearby cities
Grants Pass ranks 6 of 57 Oregon cities for unheated swim months; Central Point, Medford nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Central Point, OR | 22 mi | 1 | 6 | $305 |
| Medford, OR | 25 mi | 1 | 6 | $305 |
| Ashland, OR | 36 mi | 0 | 5 | $375 |
| Roseburg, OR | 55 mi | 0 | 5 | $262 |
| Coos Bay, OR | 80 mi | 0 | 0 | $0 |
| Klamath Falls, OR | 81 mi | 0 | 4 | $316 |