Pool swim season in Simi Valley, CA
Swim season in Simi Valley without a heater, and with one
An unheated pool in Simi Valley reaches 78°F in Jul to Sep, about 3 months a year. The air allows up to 10 swimmable months with a heater (Feb to Nov).
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What each heater buys you in Simi Valley
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 3 | Jul to Sep | $0 | $0 |
| Solar cover only | 5 | Jun to Oct | $0 | $50 |
| Solar panels + cover | 7 | Apr to Oct | $0 | $283 |
| Heat pump + cover | 10 | Feb to Nov | $1,029 | $1,579 |
| Gas heater + cover | 10 | Feb to Nov | $1,303 | $1,728 |
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 Simi Valley
Heat pump + cover: 10 of 10 possible months for about $1,579 a year all-in, which works out near $226 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: Woodland Hills Pierce College, 11.5 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Simi Valley 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 | 70° | 56° | 3.2 | 56° | 62° | – | – |
| Feb | 70° | 57° | 4.0 | 58° | 64° | $346 | $417 |
| Mar | 74° | 60° | 5.4 | 61° | 67° | $268 | $338 |
| Apr | 78° | 63° | 6.6 | 65° | 71° | $171 | $226 |
| May | 82° | 67° | 7.5 | 70° | 76° | $79 | $110 |
| Jun | 89° | 73° | 8.1 | 75° | 81° | – | – |
| Jul | 95° | 78° | 7.9 | 80° | 86° | – | – |
| Aug | 97° | 79° | 7.4 | 83° | 89° | – | – |
| Sep | 94° | 76° | 6.3 | 81° | 87° | – | – |
| Oct | 85° | 69° | 4.8 | 74° | 80° | – | – |
| Nov | 76° | 61° | 3.6 | 66° | 72° | $165 | $212 |
| Dec | 69° | 56° | 2.9 | 58° | 64° | – | – |
Heating costs most in Feb (about $346 with a heat pump, $417 with gas). Sunshine peaks in Jun at 8.1 kWh/m²/day (NASA satellite data, 34.5 km grid cell). Highlighted months are swimmable with no heater.
How Simi Valley compares with nearby cities
Simi Valley ranks 94 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 |
|---|---|---|---|---|
| Moorpark, CA | 7 mi | 0 | 8 | $823 |
| Agoura Hills, CA | 8 mi | 3 | 10 | $1,029 |
| Thousand Oaks, CA | 9 mi | 0 | 8 | $823 |
| Calabasas, CA | 10 mi | 3 | 10 | $1,029 |
| Fillmore, CA | 13 mi | 0 | 8 | $823 |
| Camarillo, CA | 17 mi | 0 | 8 | $842 |