Pool swim season in Smyrna, DE
When can you swim in an outdoor pool in Smyrna, DE?
An unheated pool in Smyrna reaches 78°F in Jul to Aug, about 2 months a year. The air allows up to 5 swimmable months with a heater (May to Sep).
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What each heater buys you in Smyrna
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 2 | Jul to Aug | $0 | $0 |
| Solar cover only | 3 | Jul to Sep | $0 | $50 |
| Solar panels + cover | 4 | Jun to Sep | $0 | $283 |
| Heat pump + cover | 5 | May to Sep | $139 | $689 |
| Gas heater + cover | 5 | May to Sep | $250 | $675 |
For a 450 sq ft pool held at 80°F, at DE prices of 18.0¢/kWh electricity and $16/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Smyrna
Solar panels + cover: 4 of 5 possible months for about $283 a year all-in, which works out near $142 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 gas as well as a heat pump: once the purchase price is counted, gas comes out cheaper all-in here (heat pump or gas).
Weather station: Dover, 11.7 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Smyrna 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 | 44° | 36° | 2.0 | 37° | 43° | – | – |
| Feb | 47° | 38° | 2.9 | 37° | 43° | – | – |
| Mar | 55° | 45° | 3.8 | 42° | 48° | – | – |
| Apr | 66° | 56° | 5.0 | 52° | 58° | – | – |
| May | 74° | 64° | 5.6 | 63° | 69° | $120 | $212 |
| Jun | 83° | 73° | 6.2 | 72° | 78° | $19 | $38 |
| Jul | 87° | 78° | 6.2 | 79° | 85° | – | – |
| Aug | 85° | 76° | 5.4 | 80° | 86° | – | – |
| Sep | 79° | 70° | 4.4 | 75° | 81° | – | – |
| Oct | 69° | 59° | 3.2 | 65° | 71° | – | – |
| Nov | 58° | 49° | 2.3 | 53° | 59° | – | – |
| Dec | 49° | 40° | 1.8 | 43° | 49° | – | – |
Heating costs most in May (about $120 with a heat pump, $212 with gas). Sunshine peaks in Jun at 6.2 kWh/m²/day (NASA satellite data, 24.6 km grid cell). Highlighted months are swimmable with no heater.
How Smyrna compares with nearby cities
Smyrna ranks 2 of 6 Delaware cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Dover, DE | 10 mi | 2 | 5 | $139 |
| Middletown, DE | 12 mi | 2 | 5 | $158 |
| Bridgeton, NJ | 22 mi | 1 | 5 | $257 |
| Elkton, MD | 24 mi | 2 | 5 | $186 |
| Newark, DE | 28 mi | 2 | 5 | $158 |
| Milford, DE | 28 mi | 1 | 5 | $182 |