Pool swim season in Fullerton, CA
Fullerton, CA: how long the pool season really is
An unheated pool in Fullerton reaches 78°F in Aug to Sep, about 2 months a year. The air allows up to 9 swimmable months with a heater (Mar to Nov).
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Heater options for a Fullerton pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 2 | Aug to Sep | $0 | $0 |
| Solar cover only | 5 | Jun to Oct | $0 | $50 |
| Solar panels + cover | 8 | Apr to Nov | $0 | $283 |
| Heat pump + cover | 9 | Mar to Nov | $635 | $1,185 |
| Gas heater + cover | 9 | Mar to Nov | $839 | $1,264 |
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 Fullerton
Solar panels + cover: 8 of 9 possible months for about $283 a year all-in, which works out near $47 for each month it adds.
Before you pay for any heater, buy a solar cover: on its own it adds 3 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: Fullerton Municipal Airport, 3.4 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Fullerton 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 | 69° | 58° | 3.2 | 58° | 64° | – | – |
| Feb | 69° | 59° | 4.1 | 59° | 65° | – | – |
| Mar | 71° | 61° | 5.4 | 62° | 68° | $232 | $298 |
| Apr | 74° | 64° | 6.5 | 66° | 72° | $151 | $201 |
| May | 76° | 67° | 6.9 | 69° | 75° | $85 | $118 |
| Jun | 79° | 71° | 7.3 | 73° | 79° | $15 | $22 |
| Jul | 84° | 75° | 7.4 | 77° | 83° | – | – |
| Aug | 87° | 77° | 7.1 | 80° | 86° | – | – |
| Sep | 85° | 75° | 6.0 | 79° | 85° | – | – |
| Oct | 80° | 69° | 4.6 | 74° | 80° | $4 | $6 |
| Nov | 74° | 62° | 3.6 | 66° | 72° | $148 | $194 |
| Dec | 68° | 57° | 2.9 | 60° | 66° | – | – |
Heating costs most in Mar (about $232 with a heat pump, $298 with gas). Sunshine peaks in Jul at 7.4 kWh/m²/day (NASA satellite data, 58.4 km grid cell). Highlighted months are swimmable with no heater.
How Fullerton compares with nearby cities
Fullerton ranks 162 of 376 California cities for unheated swim months; Placentia, Brea nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| La Habra, CA | 3 mi | 2 | 9 | $635 |
| Placentia, CA | 4 mi | 3 | 12 | $1,269 |
| Brea, CA | 5 mi | 3 | 12 | $1,269 |
| La Mirada, CA | 5 mi | 2 | 9 | $676 |
| Buena Park, CA | 5 mi | 2 | 9 | $676 |
| La Palma, CA | 7 mi | 2 | 9 | $676 |