Pool swim season in Alton, TX
Alton, TX: how long the pool season really is
An unheated pool in Alton reaches 78°F in May to Oct, about 6 months a year. The air allows up to 11 swimmable months with a heater (Feb to Dec).
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Heater options for a Alton pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 6 | May to Oct | $0 | $0 |
| Solar cover only | 7 | Apr to Oct | $0 | $50 |
| Solar panels + cover | 9 | Mar to Nov | $0 | $283 |
| Heat pump + cover | 11 | Feb to Dec | $315 | $865 |
| Gas heater + cover | 11 | Feb to Dec | $747 | $1,172 |
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 Alton
Heat pump + cover: 11 of 11 possible months for about $865 a year all-in, which works out near $173 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: La Joya, 2.5 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Alton 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 | 69° | 58° | 3.2 | 59° | 65° | – | – |
| Feb | 74° | 63° | 4.0 | 61° | 67° | $122 | $287 |
| Mar | 79° | 68° | 4.8 | 67° | 73° | $59 | $151 |
| Apr | 85° | 74° | 5.6 | 74° | 80° | $2 | $7 |
| May | 90° | 80° | 6.1 | 80° | 86° | – | – |
| Jun | 95° | 84° | 6.9 | 86° | 92° | – | – |
| Jul | 95° | 85° | 6.8 | 89° | 95° | – | – |
| Aug | 97° | 86° | 6.6 | 89° | 95° | – | – |
| Sep | 92° | 82° | 5.4 | 86° | 92° | – | – |
| Oct | 87° | 75° | 4.7 | 80° | 86° | – | – |
| Nov | 78° | 67° | 3.7 | 72° | 78° | $23 | $56 |
| Dec | 71° | 59° | 3.0 | 63° | 69° | $109 | $246 |
Heating costs most in Feb (about $122 with a heat pump, $287 with gas). Sunshine peaks in Jun at 6.9 kWh/m²/day (NASA satellite data, 30.1 km grid cell). Highlighted months are swimmable with no heater.
How Alton compares with nearby cities
Alton ranks 21 of 252 Texas cities for unheated swim months; Pharr, San Juan nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Palmview, TX | 6 mi | 6 | 11 | $315 |
| Mission, TX | 6 mi | 6 | 12 | $351 |
| McAllen, TX | 6 mi | 6 | 12 | $351 |
| Edinburg, TX | 10 mi | 6 | 12 | $373 |
| Pharr, TX | 11 mi | 7 | 12 | $254 |
| San Juan, TX | 12 mi | 7 | 12 | $254 |