Pool swim season in Sierra Vista, AZ
When can you swim in an outdoor pool in Sierra Vista, AZ?
An unheated pool in Sierra Vista reaches 78°F in Jul to Aug, about 2 months a year. The air allows up to 9 swimmable months with a heater (Mar to Nov).
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What each heater buys you in Sierra Vista
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 2 | Jul to Aug | $0 | $0 |
| Solar cover only | 4 | Jun to Sep | $0 | $50 |
| Solar panels + cover | 7 | Apr to Oct | $0 | $283 |
| Heat pump + cover | 9 | Mar to Nov | $552 | $1,102 |
| Gas heater + cover | 9 | Mar to Nov | $1,192 | $1,617 |
For a 450 sq ft pool held at 80°F, at AZ prices of 15.4¢/kWh electricity and $19/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Sierra Vista
Heat pump + cover: 9 of 9 possible months for about $1,102 a year all-in, which works out near $157 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: Sierra Vista, 2.8 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Sierra Vista 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 | 61° | 45° | 3.8 | 46° | 52° | – | – |
| Feb | 64° | 49° | 4.7 | 49° | 55° | – | – |
| Mar | 71° | 54° | 6.2 | 54° | 60° | $204 | $422 |
| Apr | 78° | 60° | 7.6 | 62° | 68° | $117 | $266 |
| May | 85° | 68° | 8.3 | 69° | 75° | $41 | $103 |
| Jun | 94° | 77° | 8.1 | 77° | 83° | – | – |
| Jul | 92° | 77° | 6.5 | 80° | 86° | – | – |
| Aug | 90° | 76° | 6.3 | 80° | 86° | – | – |
| Sep | 87° | 72° | 5.8 | 76° | 82° | – | – |
| Oct | 80° | 64° | 5.2 | 70° | 76° | $38 | $90 |
| Nov | 70° | 53° | 4.1 | 60° | 66° | $152 | $311 |
| Dec | 62° | 46° | 3.5 | 50° | 56° | – | – |
Heating costs most in Mar (about $204 with a heat pump, $422 with gas). Sunshine peaks in May at 8.3 kWh/m²/day (NASA satellite data, 19.0 km grid cell). Highlighted months are swimmable with no heater.
How Sierra Vista compares with nearby cities
Sierra Vista ranks 39 of 44 Arizona cities for unheated swim months; Nogales, Sahuarita, Douglas nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Nogales, AZ | 39 mi | 4 | 9 | $404 |
| Sahuarita, AZ | 46 mi | 4 | 9 | $262 |
| Douglas, AZ | 47 mi | 4 | 9 | $404 |
| Tucson, AZ | 52 mi | 5 | 9 | $206 |
| Oro Valley, AZ | 71 mi | 4 | 9 | $411 |
| Marana, AZ | 79 mi | 4 | 9 | $409 |