Pool swim season in Santa Rosa, CA
Swim season in Santa Rosa without a heater, and with one
An unheated pool in Santa Rosa never reaches 78°F in a normal year. It peaks around 71°F in Aug. The air allows up to 7 swimmable months with a heater (Apr to Oct).
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What each heater buys you in Santa Rosa
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 0 | no month | $0 | $0 |
| Solar cover only | 0 | no month | $0 | $50 |
| Solar panels + cover | 6 | May to Oct | $0 | $283 |
| Heat pump + cover | 7 | Apr to Oct | $934 | $1,484 |
| Gas heater + cover | 7 | Apr to Oct | $1,210 | $1,635 |
For a 450 sq ft pool held at 80°F, at CA prices of 32.6¢/kWh electricity and $22/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Santa Rosa
Solar panels + cover: 6 of 7 possible months for about $283 a year all-in, which works out near $47 for each month it adds.
A solar cover alone adds no swim months here, so if you want a longer season you need a heater (why); still use one at night to hold the heat you pay for. 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: Santa Rosa, 0.8 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Santa Rosa 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 | 60° | 49° | 2.3 | 48° | 54° | – | – |
| Feb | 64° | 52° | 3.3 | 51° | 57° | – | – |
| Mar | 67° | 54° | 4.6 | 55° | 61° | – | – |
| Apr | 71° | 57° | 6.1 | 59° | 65° | $316 | $384 |
| May | 75° | 61° | 7.3 | 64° | 70° | $209 | $268 |
| Jun | 80° | 66° | 8.1 | 69° | 75° | $103 | $141 |
| Jul | 82° | 67° | 8.0 | 71° | 77° | $50 | $70 |
| Aug | 83° | 68° | 7.1 | 71° | 77° | $48 | $67 |
| Sep | 84° | 68° | 5.8 | 70° | 76° | $65 | $91 |
| Oct | 79° | 63° | 4.2 | 67° | 73° | $143 | $189 |
| Nov | 67° | 55° | 2.8 | 59° | 65° | – | – |
| Dec | 59° | 49° | 2.0 | 51° | 57° | – | – |
Heating costs most in Apr (about $316 with a heat pump, $384 with gas). Sunshine peaks in Jun at 8.1 kWh/m²/day (NASA satellite data, 18.9 km grid cell). Highlighted months are swimmable with no heater.
How Santa Rosa compares with nearby cities
Santa Rosa ranks 310 of 376 California cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Rohnert Park, CA | 7 mi | 0 | 7 | $934 |
| Windsor, CA | 9 mi | 0 | 6 | $657 |
| Petaluma, CA | 15 mi | 0 | 6 | $746 |
| Healdsburg, CA | 15 mi | 0 | 7 | $652 |
| Sonoma, CA | 17 mi | 0 | 6 | $496 |
| Napa, CA | 24 mi | 0 | 7 | $680 |