Pool swim season in Casper, WY
Swim season in Casper without a heater, and with one
An unheated pool in Casper never reaches 78°F in a normal year. It peaks around 75°F in Aug. The air allows up to 4 swimmable months with a heater (Jun to Sep).
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
What each heater buys you in Casper
| 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 | 4 | Jun to Sep | $151 | $701 |
| Gas heater + cover | 4 | Jun to Sep | $247 | $672 |
For a 450 sq ft pool held at 80°F, at WY prices of 14.0¢/kWh electricity and $12/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Casper
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 2 months 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: Casper Water Treatment Plant, 2 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Casper 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 | 38° | 27° | 2.2 | 27° | 33° | – | – |
| Feb | 40° | 29° | 3.0 | 28° | 34° | – | – |
| Mar | 49° | 37° | 4.2 | 34° | 40° | – | – |
| Apr | 57° | 44° | 5.4 | 43° | 49° | – | – |
| May | 67° | 54° | 6.4 | 52° | 58° | – | – |
| Jun | 79° | 64° | 7.5 | 64° | 70° | $85 | $141 |
| Jul | 88° | 72° | 7.3 | 73° | 79° | $10 | $18 |
| Aug | 87° | 71° | 6.4 | 75° | 81° | – | – |
| Sep | 76° | 60° | 5.2 | 68° | 74° | $56 | $88 |
| Oct | 61° | 47° | 3.5 | 54° | 60° | – | – |
| Nov | 48° | 36° | 2.4 | 41° | 47° | – | – |
| Dec | 38° | 28° | 1.7 | 31° | 37° | – | – |
Heating costs most in Jun (about $85 with a heat pump, $141 with gas). Sunshine peaks in Jun at 7.5 kWh/m²/day (NASA satellite data, 40.7 km grid cell). Highlighted months are swimmable with no heater.
How Casper compares with nearby cities
Casper ranks 1 of 11 Wyoming cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Riverton, WY | 105 mi | 0 | 4 | $182 |
| Gillette, WY | 107 mi | 0 | 4 | $166 |
| Laramie, WY | 112 mi | 0 | 4 | $452 |
| Sheridan, WY | 139 mi | 0 | 4 | $216 |
| Cheyenne, WY | 142 mi | 0 | 4 | $236 |
| Scottsbluff, NE | 152 mi | 0 | 4 | $93 |