Pool swim season in Westminster, CA
Swim season in Westminster without a heater, and with one
An unheated pool in Westminster reaches 78°F in Aug, about 1 month a year. The air allows up to 9 swimmable months with a heater (Mar to Nov).
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Heater options for a Westminster pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 1 | Aug | $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 | $644 | $1,194 |
| Gas heater + cover | 9 | Mar to Nov | $858 | $1,283 |
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 Westminster
Solar panels + cover: 8 of 9 possible months for about $283 a year all-in, which works out near $40 for each month it adds.
Before you pay for any heater, buy a solar cover: on its own it adds 4 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: Santa Ana Fire Station, 7.3 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Westminster 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° | 59° | 3.2 | 59° | 65° | – | – |
| Feb | 69° | 59° | 4.1 | 60° | 66° | – | – |
| Mar | 71° | 62° | 5.4 | 63° | 69° | $220 | $284 |
| Apr | 73° | 64° | 6.5 | 66° | 72° | $151 | $201 |
| May | 75° | 66° | 6.9 | 69° | 75° | $93 | $128 |
| Jun | 78° | 70° | 7.3 | 72° | 78° | $31 | $45 |
| Jul | 83° | 74° | 7.4 | 76° | 82° | – | – |
| Aug | 85° | 75° | 7.1 | 78° | 84° | – | – |
| Sep | 84° | 74° | 6.0 | 77° | 83° | – | – |
| Oct | 79° | 69° | 4.6 | 73° | 79° | $14 | $20 |
| Nov | 74° | 63° | 3.6 | 67° | 73° | $135 | $180 |
| Dec | 68° | 58° | 2.9 | 61° | 67° | – | – |
Heating costs most in Mar (about $220 with a heat pump, $284 with gas). Sunshine peaks in Jul at 7.4 kWh/m²/day (NASA satellite data, 53.6 km grid cell). Highlighted months are swimmable with no heater.
How Westminster compares with nearby cities
Westminster ranks 195 of 376 California cities for unheated swim months; Stanton nearby gets a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Garden Grove, CA | 3 mi | 1 | 9 | $644 |
| Stanton, CA | 3 mi | 2 | 9 | $635 |
| Fountain Valley, CA | 4 mi | 0 | 8 | $547 |
| Huntington Beach, CA | 4 mi | 0 | 8 | $585 |
| Seal Beach, CA | 4 mi | 0 | 8 | $566 |
| Los Alamitos, CA | 5 mi | 0 | 8 | $566 |