Pool swim season in Garden City, ID
Garden City, ID: how long the pool season really is
An unheated pool in Garden City never reaches 78°F in a normal year. It peaks around 76°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 Garden City
| 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 | $126 | $676 |
| Gas heater + cover | 4 | Jun to Sep | $147 | $572 |
For a 450 sq ft pool held at 80°F, at ID prices of 13.0¢/kWh electricity and $8/Mcf gas. All-in spreads the purchase over the equipment's life.
The cheapest way to the full season in Garden City
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: Boise 7 N, 6.7 mi away (NOAA 1991–2020 normals). Water temperature is estimated from air and sunshine, not measured.
Garden City 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 | 37° | 30° | 1.7 | 29° | 35° | – | – |
| Feb | 43° | 35° | 2.7 | 32° | 38° | – | – |
| Mar | 51° | 42° | 4.0 | 39° | 45° | – | – |
| Apr | 58° | 47° | 5.5 | 47° | 53° | – | – |
| May | 68° | 55° | 6.7 | 55° | 61° | – | – |
| Jun | 77° | 63° | 7.5 | 63° | 69° | $82 | $95 |
| Jul | 88° | 73° | 7.7 | 72° | 78° | $11 | $14 |
| Aug | 86° | 72° | 6.7 | 76° | 82° | – | – |
| Sep | 76° | 63° | 5.2 | 70° | 76° | $33 | $38 |
| Oct | 61° | 51° | 3.5 | 57° | 63° | – | – |
| Nov | 46° | 38° | 2.1 | 43° | 49° | – | – |
| Dec | 37° | 30° | 1.4 | 32° | 38° | – | – |
Heating costs most in Jun (about $82 with a heat pump, $95 with gas). Sunshine peaks in Jul at 7.7 kWh/m²/day (NASA satellite data, 25.0 km grid cell). Highlighted months are swimmable with no heater.
How Garden City compares with nearby cities
Garden City ranks 15 of 26 Idaho cities for unheated swim months; Boise City, Eagle, Meridian nearby get a longer season without a heater.
| City | Distance | Unheated months | Heat pump months | Heat pump $/yr |
|---|---|---|---|---|
| Boise City, ID | 6 mi | 1 | 5 | $167 |
| Eagle, ID | 6 mi | 1 | 5 | $200 |
| Meridian, ID | 7 mi | 1 | 5 | $167 |
| Star, ID | 10 mi | 1 | 5 | $200 |
| Kuna, ID | 11 mi | 1 | 5 | $167 |
| Nampa, ID | 15 mi | 1 | 5 | $200 |