Pool swim season in Worcester, MA
Worcester, MA: how long the pool season really is
An unheated pool in Worcester never reaches 78°F in a normal year. It peaks around 72°F in Aug. The air allows up to 4 swimmable months with a heater (Jun to Sep).
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What each heater buys you in Worcester
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 0 | no month | $0 | $0 |
| Solar cover only | 1 | Aug | $0 | $50 |
| Solar panels + cover | 4 | Jun to Sep | $0 | $283 |
| Heat pump + cover | 4 | Jun to Sep | $386 | $936 |
| Gas heater + cover | 4 | Jun to Sep | $643 | $1,068 |
For a 450 sq ft pool held at 80°F, at MA prices of 30.2¢/kWh electricity and $25/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Worcester
Solar panels + cover: 4 of 4 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 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: Worcester, 3.3 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Worcester 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 | 32° | 25° | 1.8 | 26° | 32° | – | – |
| Feb | 35° | 27° | 2.7 | 26° | 32° | – | – |
| Mar | 43° | 35° | 3.7 | 31° | 37° | – | – |
| Apr | 56° | 46° | 4.7 | 42° | 48° | – | – |
| May | 67° | 57° | 5.3 | 54° | 60° | – | – |
| Jun | 75° | 65° | 5.7 | 64° | 70° | $180 | $300 |
| Jul | 80° | 71° | 6.0 | 71° | 77° | $49 | $88 |
| Aug | 78° | 69° | 5.3 | 72° | 78° | $27 | $48 |
| Sep | 71° | 62° | 4.3 | 67° | 73° | $130 | $207 |
| Oct | 59° | 51° | 2.8 | 56° | 62° | – | – |
| Nov | 48° | 40° | 2.0 | 44° | 50° | – | – |
| Dec | 38° | 31° | 1.5 | 34° | 40° | – | – |
Heating costs most in Jun (about $180 with a heat pump, $300 with gas). Sunshine peaks in Jul at 6.0 kWh/m²/day (NASA satellite data, 36.0 km grid cell). Highlighted months are swimmable with no heater.
How Worcester compares with nearby cities
Worcester ranks 47 of 58 Massachusetts cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Marlborough, MA | 14 mi | 0 | 5 | $573 |
| Leominster, MA | 17 mi | 0 | 4 | $282 |
| Southbridge Town, MA | 19 mi | 0 | 4 | $386 |
| Framingham, MA | 19 mi | 0 | 4 | $335 |
| Fitchburg, MA | 23 mi | 0 | 4 | $380 |
| Gardner, MA | 24 mi | 0 | 4 | $483 |