Pool swim season in Rio Grande City, TX
When can you swim in an outdoor pool in Rio Grande City, TX?
An unheated pool in Rio Grande City reaches 78°F in May to Oct, about 6 months a year. The air allows up to 12 swimmable months with a heater (all year).
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What each heater buys you in Rio Grande City
| 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 | 12 | all year | $460 | $1,010 |
| Gas heater + cover | 12 | all year | $1,062 | $1,487 |
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 Rio Grande City
Heat pump + cover: 12 of 12 possible months for about $1,010 a year all-in, which works out near $168 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: Rio Grande City, 0.7 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Rio Grande City 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 | 71° | 58° | 3.2 | 59° | 65° | $156 | $343 |
| Feb | 76° | 63° | 4.0 | 62° | 68° | $119 | $282 |
| Mar | 82° | 69° | 4.8 | 68° | 74° | $54 | $138 |
| Apr | 89° | 76° | 5.6 | 75° | 81° | – | – |
| May | 94° | 82° | 6.1 | 82° | 88° | – | – |
| Jun | 98° | 86° | 6.9 | 88° | 94° | – | – |
| Jul | 99° | 87° | 6.8 | 90° | 96° | – | – |
| Aug | 99° | 87° | 6.6 | 91° | 97° | – | – |
| Sep | 94° | 83° | 5.4 | 87° | 93° | – | – |
| Oct | 88° | 76° | 4.7 | 81° | 87° | – | – |
| Nov | 79° | 67° | 3.7 | 72° | 78° | $19 | $48 |
| Dec | 72° | 59° | 3.0 | 63° | 69° | $112 | $251 |
Heating costs most in Jan (about $156 with a heat pump, $343 with gas). Sunshine peaks in Jun at 6.9 kWh/m²/day (NASA satellite data, 34.6 km grid cell). Highlighted months are swimmable with no heater.
How Rio Grande City compares with nearby cities
Rio Grande City ranks 10 of 252 Texas cities for unheated swim months; Hidalgo nearby gets a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Roma, TX | 12 mi | 6 | 12 | $454 |
| Palmview, TX | 29 mi | 6 | 11 | $315 |
| Alton, TX | 32 mi | 6 | 11 | $315 |
| Mission, TX | 33 mi | 6 | 12 | $351 |
| McAllen, TX | 37 mi | 6 | 12 | $351 |
| Hidalgo, TX | 40 mi | 7 | 12 | $254 |