Pool swim season in Des Moines, IA
Swim season in Des Moines without a heater, and with one
An unheated pool in Des Moines never reaches 78°F in a normal year. It peaks around 78°F in Jul. The air allows up to 5 swimmable months with a heater (May to Sep).
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Heater options for a Des Moines pool, side by side
| 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 | $172 | $722 |
| Gas heater + cover | 5 | May to Sep | $249 | $674 |
For a 450 sq ft pool held at 80°F, at IA prices of 14.6¢/kWh electricity and $11/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Des Moines
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 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: Des Moines International Airport, 3.5 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Des Moines 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 | 31° | 22° | 2.0 | 24° | 30° | – | – |
| Feb | 36° | 27° | 3.0 | 25° | 31° | – | – |
| Mar | 49° | 39° | 3.8 | 34° | 40° | – | – |
| Apr | 62° | 51° | 4.8 | 47° | 53° | – | – |
| May | 72° | 62° | 5.6 | 60° | 66° | $126 | $178 |
| Jun | 82° | 72° | 6.3 | 71° | 77° | $26 | $42 |
| Jul | 86° | 76° | 6.4 | 78° | 84° | – | – |
| Aug | 84° | 74° | 5.5 | 78° | 84° | – | – |
| Sep | 77° | 66° | 4.6 | 72° | 78° | $20 | $29 |
| Oct | 63° | 53° | 3.1 | 60° | 66° | – | – |
| Nov | 48° | 39° | 2.2 | 45° | 51° | – | – |
| Dec | 36° | 28° | 1.7 | 32° | 38° | – | – |
Heating costs most in May (about $126 with a heat pump, $178 with gas). Sunshine peaks in Jul at 6.4 kWh/m²/day (NASA satellite data, 12.2 km grid cell). Highlighted months are swimmable with no heater.
How Des Moines compares with nearby cities
Des Moines ranks 2 of 41 Iowa cities for unheated swim months, and no nearby city gets a longer unheated season.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Pleasant Hill, IA | 6 mi | 0 | 5 | $172 |
| Norwalk, IA | 8 mi | 0 | 5 | $172 |
| Altoona, IA | 9 mi | 0 | 5 | $207 |
| West Des Moines, IA | 9 mi | 0 | 5 | $172 |
| Urbandale, IA | 10 mi | 0 | 5 | $188 |
| Johnston, IA | 10 mi | 0 | 5 | $188 |