Island Park, Idaho has a Subarctic With Cool Summers And Year Around Rainfall climate (Köppen classification: Dfc). Average annual temperatures range from -4.9 °C (low) to 11.1 °C (high). Annual precipitation averages 702.3 Millimeters. Island Park is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around Jun. 11 - Jun. 20 through the first frost around Aug. 1 - Aug. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -14.8 °C | -2.3 °C | 91.19 mm |
| February | -14.1 °C | -0.1 °C | 67.06 mm |
| March | -10.1 °C | 4.9 °C | 58.93 mm |
| April | -5.2 °C | 9.6 °C | 58.93 mm |
| May | -0.3 °C | 15.2 °C | 72.64 mm |
| June | 3.1 °C | 20.3 °C | 58.67 mm |
| July | 5.7 °C | 26.3 °C | 26.16 mm |
| August | 4.6 °C | 26.3 °C | 27.69 mm |
| September | 0.6 °C | 20.6 °C | 34.29 mm |
| October | -4 °C | 11.7 °C | 49.02 mm |
| November | -9.7 °C | 2.9 °C | 62.23 mm |
| December | -14.3 °C | -2.7 °C | 95.5 mm |
| Annual | -4.9 °C | 11.1 °C | 702.31 mm |
| Average First Frost Date | Aug. 1 - Aug. 10 |
| Average Last Frost Date | Jun. 11 - Jun. 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfc - Subarctic With Cool Summers And Year Around Rainfall |