Pool swim season in Largo, FL
Largo, FL: how long the pool season really is
An unheated pool in Largo 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 Largo
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 6 | May to Oct | $0 | $0 |
| Solar cover only | 8 | Apr to Nov | $0 | $50 |
| Solar panels + cover | 10 | Mar to Dec | $0 | $283 |
| Heat pump + cover | 12 | all year | $295 | $845 |
| Gas heater + cover | 12 | all year | $969 | $1,394 |
For a 450 sq ft pool held at 80°F, at FL prices of 15.3¢/kWh electricity and $25/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Largo
Heat pump + cover: 12 of 12 possible months for about $845 a year all-in, which works out near $141 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: St Petersburg Clearwater International, 5.4 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Largo 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° | 62° | 3.6 | 64° | 70° | $97 | $308 |
| Feb | 73° | 64° | 4.3 | 64° | 70° | $87 | $288 |
| Mar | 77° | 68° | 5.5 | 69° | 75° | $46 | $159 |
| Apr | 82° | 73° | 6.4 | 74° | 80° | – | $1 |
| May | 87° | 78° | 6.8 | 80° | 86° | – | – |
| Jun | 90° | 82° | 6.2 | 83° | 89° | – | – |
| Jul | 90° | 83° | 5.9 | 86° | 92° | – | – |
| Aug | 91° | 84° | 5.6 | 86° | 92° | – | – |
| Sep | 89° | 82° | 5.2 | 85° | 91° | – | – |
| Oct | 84° | 77° | 4.7 | 81° | 87° | – | – |
| Nov | 77° | 69° | 3.9 | 74° | 80° | $2 | $6 |
| Dec | 73° | 64° | 3.3 | 67° | 73° | $63 | $207 |
Heating costs most in Jan (about $97 with a heat pump, $308 with gas). Sunshine peaks in May at 6.8 kWh/m²/day (NASA satellite data, 52.9 km grid cell). Highlighted months are swimmable with no heater.
How Largo compares with nearby cities
Largo ranks 58 of 173 Florida cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Seminole, FL | 5 mi | 6 | 12 | $295 |
| Clearwater, FL | 5 mi | 6 | 12 | $295 |
| Pinellas Park, FL | 5 mi | 6 | 12 | $295 |
| Safety Harbor, FL | 8 mi | 6 | 12 | $302 |
| Dunedin, FL | 9 mi | 6 | 11 | $270 |
| Oldsmar, FL | 12 mi | 6 | 11 | $270 |