Pool swim season in Lima, OH
Lima, OH: how long the pool season really is
An unheated pool in Lima never reaches 78°F in a normal year. It peaks around 75°F in Aug. The air allows up to 5 swimmable months with a heater (May to Sep).
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What each heater buys you in Lima
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 0 | no month | $0 | $0 |
| Solar cover only | 2 | Jul to Aug | $0 | $50 |
| Solar panels + cover | 4 | Jun to Sep | $0 | $283 |
| Heat pump + cover | 5 | May to Sep | $282 | $832 |
| Gas heater + cover | 5 | May to Sep | $407 | $832 |
For a 450 sq ft pool held at 80°F, at OH prices of 18.8¢/kWh electricity and $14/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Lima
Solar panels + cover: 4 of 5 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: Lima Water Treatment Plant, 1.4 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Lima 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 | 34° | 26° | 1.7 | 28° | 34° | – | – |
| Feb | 37° | 29° | 2.6 | 27° | 33° | – | – |
| Mar | 48° | 38° | 3.6 | 34° | 40° | – | – |
| Apr | 61° | 50° | 4.8 | 46° | 52° | – | – |
| May | 72° | 61° | 5.5 | 58° | 64° | $186 | $260 |
| Jun | 80° | 70° | 6.2 | 69° | 75° | $55 | $86 |
| Jul | 84° | 73° | 6.2 | 75° | 81° | – | – |
| Aug | 82° | 72° | 5.6 | 75° | 81° | – | – |
| Sep | 77° | 66° | 4.5 | 70° | 76° | $41 | $61 |
| Oct | 64° | 54° | 3.0 | 60° | 66° | – | – |
| Nov | 50° | 42° | 2.1 | 47° | 53° | – | – |
| Dec | 39° | 32° | 1.5 | 35° | 41° | – | – |
Heating costs most in May (about $186 with a heat pump, $260 with gas). Sunshine peaks in Jul at 6.2 kWh/m²/day (NASA satellite data, 42.3 km grid cell). Highlighted months are swimmable with no heater.
How Lima compares with nearby cities
Lima ranks 131 of 176 Ohio cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Van Wert, OH | 26 mi | 0 | 5 | $261 |
| Celina, OH | 27 mi | 0 | 5 | $255 |
| Sidney, OH | 31 mi | 0 | 5 | $283 |
| Bellefontaine, OH | 32 mi | 0 | 5 | $288 |
| Findlay, OH | 33 mi | 0 | 5 | $267 |
| Defiance, OH | 40 mi | 0 | 5 | $292 |