Pool swim season in Bozeman, MT
Swim season in Bozeman without a heater, and with one
An unheated pool in Bozeman never reaches 78°F in a normal year. It peaks around 69°F in Aug. The air allows up to 4 swimmable months with a heater (Jun to Sep).
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Heater options for a Bozeman pool, side by side
| Option | Months | Swimmable | Energy/yr | All-in/yr |
|---|---|---|---|---|
| No heater | 0 | no month | $0 | $0 |
| Solar cover only | 0 | no month | $0 | $50 |
| Solar panels + cover | 2 | Jul to Aug | $0 | $283 |
| Heat pump + cover | 4 | Jun to Sep | $336 | $886 |
| Gas heater + cover | 4 | Jun to Sep | $402 | $827 |
For a 450 sq ft pool held at 80°F, at MT prices of 14.1¢/kWh electricity and $9/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Bozeman
Gas heater + cover: 4 of 4 possible months for about $827 a year all-in, which works out near $207 for each month it adds.
A solar cover alone adds no swim months here, so if you want a longer season you need a heater (why); still use one at night to hold the heat you pay for. 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: Bozeman Montana State Univ, 1.5 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Bozeman 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° | 25° | 1.7 | 23° | 29° | – | – |
| Feb | 37° | 27° | 2.8 | 25° | 31° | – | – |
| Mar | 46° | 35° | 3.8 | 32° | 38° | – | – |
| Apr | 55° | 43° | 4.8 | 41° | 47° | – | – |
| May | 63° | 51° | 5.6 | 49° | 55° | – | – |
| Jun | 72° | 59° | 6.6 | 58° | 64° | $139 | $162 |
| Jul | 82° | 67° | 7.1 | 67° | 73° | $57 | $74 |
| Aug | 81° | 66° | 6.1 | 69° | 75° | $38 | $49 |
| Sep | 71° | 57° | 4.6 | 63° | 69° | $102 | $117 |
| Oct | 57° | 45° | 2.9 | 51° | 57° | – | – |
| Nov | 42° | 32° | 1.8 | 37° | 43° | – | – |
| Dec | 33° | 24° | 1.3 | 26° | 32° | – | – |
Heating costs most in Jun (about $139 with a heat pump, $162 with gas). Sunshine peaks in Jul at 7.1 kWh/m²/day (NASA satellite data, 40.3 km grid cell). Highlighted months are swimmable with no heater.
How Bozeman compares with nearby cities
Bozeman ranks 6 of 8 Montana cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Belgrade, MT | 9 mi | 0 | 4 | $329 |
| Helena, MT | 78 mi | 0 | 4 | $223 |
| Butte-Silver Bow, MT | 79 mi | 0 | 3 | $329 |
| Billings, MT | 121 mi | 0 | 4 | $142 |
| Cody, WY | 126 mi | 0 | 4 | $212 |
| Great Falls, MT | 126 mi | 0 | 4 | $220 |