Pool swim season in Houston, TX
When can you swim in an outdoor pool in Houston, TX?
An unheated pool in Houston 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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Heater options for a Houston pool, side by side
| 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 | 8 | Apr to Nov | $0 | $283 |
| Heat pump + cover | 9 | Mar to Nov | $215 | $765 |
| Gas heater + cover | 9 | Mar to Nov | $519 | $944 |
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 Houston
Solar panels + cover: 8 of 9 possible months for about $283 a year all-in, which works out near $71 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: Houston-Port, 7.1 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Houston 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° | 54° | 2.9 | 55° | 61° | – | – |
| Feb | 67° | 58° | 3.3 | 56° | 62° | – | – |
| Mar | 73° | 64° | 4.5 | 62° | 68° | $112 | $267 |
| Apr | 79° | 70° | 5.3 | 69° | 75° | $42 | $110 |
| May | 86° | 77° | 6.0 | 77° | 83° | – | – |
| Jun | 91° | 83° | 6.3 | 83° | 89° | – | – |
| Jul | 93° | 85° | 6.1 | 87° | 93° | – | – |
| Aug | 94° | 86° | 5.9 | 88° | 94° | – | – |
| Sep | 90° | 81° | 5.0 | 85° | 91° | – | – |
| Oct | 82° | 72° | 4.4 | 78° | 84° | – | – |
| Nov | 72° | 62° | 3.3 | 68° | 74° | $61 | $142 |
| Dec | 65° | 56° | 2.6 | 59° | 65° | – | – |
Heating costs most in Mar (about $112 with a heat pump, $267 with gas). Sunshine peaks in Jun at 6.3 kWh/m²/day (NASA satellite data, 33.5 km grid cell). Highlighted months are swimmable with no heater.
How Houston compares with nearby cities
Houston ranks 92 of 252 Texas cities for unheated swim months; South Houston, Stafford nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| West University Place, TX | 5 mi | 4 | 9 | $215 |
| Bellaire, TX | 7 mi | 4 | 9 | $215 |
| Galena Park, TX | 10 mi | 4 | 9 | $215 |
| South Houston, TX | 13 mi | 5 | 9 | $187 |
| Stafford, TX | 15 mi | 5 | 9 | $191 |
| Humble, TX | 16 mi | 4 | 9 | $218 |