Pool swim season in San Antonio, TX
Swim season in San Antonio without a heater, and with one
An unheated pool in San Antonio reaches 78°F in Jun to Sep, about 4 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 San Antonio
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 4 | Jun to Sep | $0 | $0 |
| Solar cover only | 6 | May to Oct | $0 | $50 |
| Solar panels + cover | 7 | Apr to Oct | $0 | $283 |
| Heat pump + cover | 9 | Mar to Nov | $265 | $815 |
| Gas heater + cover | 9 | Mar to Nov | $628 | $1,053 |
For a 450 sq ft pool held at 80°F, at TX prices of 16.0¢/kWh electricity and $19/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in San Antonio
Heat pump + cover: 9 of 9 possible months for about $815 a year all-in, which works out near $163 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: San Antonio Incarnate Word, 3.2 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
San Antonio 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 | 63° | 52° | 3.1 | 52° | 58° | – | – |
| Feb | 68° | 56° | 3.6 | 54° | 60° | – | – |
| Mar | 74° | 62° | 4.5 | 61° | 67° | $129 | $303 |
| Apr | 80° | 69° | 5.4 | 68° | 74° | $54 | $137 |
| May | 86° | 76° | 5.9 | 75° | 81° | – | – |
| Jun | 92° | 82° | 6.7 | 83° | 89° | – | – |
| Jul | 94° | 84° | 6.7 | 87° | 93° | – | – |
| Aug | 95° | 85° | 6.4 | 88° | 94° | – | – |
| Sep | 90° | 79° | 5.2 | 84° | 90° | – | – |
| Oct | 82° | 71° | 4.4 | 76° | 82° | – | – |
| Nov | 71° | 60° | 3.3 | 66° | 72° | $82 | $188 |
| Dec | 64° | 53° | 2.8 | 56° | 62° | – | – |
Heating costs most in Mar (about $129 with a heat pump, $303 with gas). Sunshine peaks in Jul at 6.7 kWh/m²/day (NASA satellite data, 4.8 km grid cell). Highlighted months are swimmable with no heater.
How San Antonio compares with nearby cities
San Antonio ranks 125 of 252 Texas cities for unheated swim months; Leon Valley, Helotes nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Leon Valley, TX | 6 mi | 5 | 9 | $191 |
| Helotes, TX | 12 mi | 5 | 9 | $191 |
| Live Oak, TX | 13 mi | 4 | 9 | $256 |
| Converse, TX | 14 mi | 4 | 9 | $256 |
| Universal City, TX | 14 mi | 4 | 9 | $256 |
| Selma, TX | 15 mi | 4 | 9 | $256 |