Pool swim season in Alvin, TX
When can you swim in an outdoor pool in Alvin, TX?
An unheated pool in Alvin 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 Alvin
| 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 | $235 | $785 |
| Gas heater + cover | 9 | Mar to Nov | $565 | $990 |
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 Alvin
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: Alvin, 4.1 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Alvin 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° | 53° | 2.9 | 54° | 60° | – | – |
| Feb | 67° | 57° | 3.3 | 56° | 62° | – | – |
| Mar | 73° | 63° | 4.5 | 62° | 68° | $116 | $276 |
| Apr | 78° | 69° | 5.3 | 68° | 74° | $50 | $128 |
| May | 85° | 76° | 6.0 | 75° | 81° | – | – |
| Jun | 89° | 81° | 6.3 | 82° | 88° | – | – |
| Jul | 91° | 83° | 6.1 | 85° | 91° | – | – |
| Aug | 91° | 83° | 5.9 | 85° | 91° | – | – |
| Sep | 89° | 80° | 5.0 | 83° | 89° | – | – |
| Oct | 81° | 71° | 4.4 | 77° | 83° | – | – |
| Nov | 73° | 62° | 3.3 | 67° | 73° | $69 | $161 |
| Dec | 65° | 55° | 2.6 | 58° | 64° | – | – |
Heating costs most in Mar (about $116 with a heat pump, $276 with gas). Sunshine peaks in Jun at 6.3 kWh/m²/day (NASA satellite data, 28.0 km grid cell). Highlighted months are swimmable with no heater.
How Alvin compares with nearby cities
Alvin ranks 236 of 252 Texas cities for unheated swim months; Friendswood, Manvel nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Friendswood, TX | 6 mi | 5 | 9 | $184 |
| Santa Fe, TX | 8 mi | 4 | 9 | $203 |
| League City, TX | 8 mi | 4 | 9 | $203 |
| Manvel, TX | 10 mi | 5 | 9 | $184 |
| Webster, TX | 10 mi | 4 | 9 | $203 |
| Dickinson, TX | 10 mi | 4 | 9 | $203 |