Pool swim season in Hermosa Beach, CA
When can you swim in an outdoor pool in Hermosa Beach, CA?
An unheated pool in Hermosa Beach never reaches 78°F in a normal year. It peaks around 73°F in Aug. The air allows up to 6 swimmable months with a heater (Jun to Nov).
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What each heater buys you in Hermosa Beach
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 0 | no month | $0 | $0 |
| Solar cover only | 1 | Aug | $0 | $50 |
| Solar panels + cover | 5 | Jun to Oct | $0 | $283 |
| Heat pump + cover | 6 | Jun to Nov | $555 | $1,105 |
| Gas heater + cover | 6 | Jun to Nov | $748 | $1,173 |
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 Hermosa Beach
Solar panels + cover: 5 of 6 possible months for about $283 a year all-in, which works out near $57 for each month it adds.
Before you pay for any heater, buy a solar cover: on its own it adds 1 month 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: Redondo Beach, 3 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Hermosa Beach 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 | 67° | 57° | 3.1 | 57° | 63° | – | – |
| Feb | 66° | 57° | 4.0 | 58° | 64° | – | – |
| Mar | 66° | 58° | 5.2 | 60° | 66° | – | – |
| Apr | 68° | 60° | 6.3 | 62° | 68° | – | – |
| May | 70° | 63° | 6.6 | 65° | 71° | – | – |
| Jun | 72° | 65° | 6.3 | 67° | 73° | $127 | $173 |
| Jul | 76° | 69° | 6.6 | 71° | 77° | $59 | $84 |
| Aug | 77° | 70° | 6.3 | 73° | 79° | $23 | $33 |
| Sep | 76° | 69° | 5.5 | 72° | 78° | $39 | $56 |
| Oct | 74° | 66° | 4.3 | 69° | 75° | $101 | $138 |
| Nov | 71° | 61° | 3.4 | 64° | 70° | $206 | $264 |
| Dec | 66° | 57° | 2.8 | 59° | 65° | – | – |
Heating costs most in Nov (about $206 with a heat pump, $264 with gas). Sunshine peaks in Jul at 6.6 kWh/m²/day (NASA satellite data, 42.0 km grid cell). Highlighted months are swimmable with no heater.
How Hermosa Beach compares with nearby cities
Hermosa Beach ranks 298 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 |
|---|---|---|---|---|
| Redondo Beach, CA | 1 mi | 0 | 6 | $555 |
| Manhattan Beach, CA | 2 mi | 0 | 6 | $427 |
| El Segundo, CA | 3 mi | 0 | 6 | $427 |
| Lawndale, CA | 3 mi | 0 | 7 | $455 |
| Torrance, CA | 4 mi | 0 | 6 | $555 |
| Hawthorne, CA | 5 mi | 0 | 7 | $455 |