Pool swim season in Rocklin, CA
Rocklin, CA: how long the pool season really is
An unheated pool in Rocklin reaches 78°F in Jul to Sep, about 3 months a year. The air allows up to 6 swimmable months with a heater (May to Oct).
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What each heater buys you in Rocklin
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 3 | Jul to Sep | $0 | $0 |
| Solar cover only | 4 | Jun to Sep | $0 | $50 |
| Solar panels + cover | 6 | May to Oct | $0 | $283 |
| Heat pump + cover | 6 | May to Oct | $265 | $815 |
| Gas heater + cover | 6 | May to Oct | $357 | $782 |
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 Rocklin
Solar panels + cover: 6 of 6 possible months for about $283 a year all-in, which works out near $94 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 gas as well as a heat pump: once the purchase price is counted, gas comes out cheaper all-in here (heat pump or gas).
Weather station: Auburn, 11.3 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Rocklin 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 | 56° | 47° | 2.2 | 46° | 52° | – | – |
| Feb | 59° | 50° | 3.3 | 49° | 55° | – | – |
| Mar | 63° | 53° | 4.6 | 53° | 59° | – | – |
| Apr | 68° | 56° | 6.2 | 58° | 64° | – | – |
| May | 77° | 64° | 7.5 | 65° | 71° | $176 | $235 |
| Jun | 86° | 72° | 8.3 | 73° | 79° | $14 | $21 |
| Jul | 93° | 78° | 8.2 | 80° | 86° | – | – |
| Aug | 92° | 77° | 7.4 | 82° | 88° | – | – |
| Sep | 87° | 73° | 6.0 | 78° | 84° | – | – |
| Oct | 77° | 64° | 4.3 | 70° | 76° | $75 | $101 |
| Nov | 64° | 53° | 2.8 | 59° | 65° | – | – |
| Dec | 56° | 47° | 2.0 | 49° | 55° | – | – |
Heating costs most in May (about $176 with a heat pump, $235 with gas). Sunshine peaks in Jun at 8.3 kWh/m²/day (NASA satellite data, 40.5 km grid cell). Highlighted months are swimmable with no heater.
How Rocklin compares with nearby cities
Rocklin ranks 105 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 |
|---|---|---|---|---|
| Roseville, CA | 5 mi | 2 | 7 | $519 |
| Lincoln, CA | 5 mi | 3 | 6 | $265 |
| Citrus Heights, CA | 8 mi | 3 | 7 | $369 |
| Auburn, CA | 11 mi | 3 | 6 | $265 |
| Folsom, CA | 11 mi | 3 | 7 | $369 |
| Rancho Cordova, CA | 16 mi | 3 | 7 | $369 |