Island Park, Idaho has a Subarctic With Cool Summers And Year Around Rainfall climate (Köppen classification: Dfc). Average annual temperatures range from 23.2 °F (low) to 51.9 °F (high). Annual precipitation averages 27.7 Inches. 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 | 5.4 °F | 27.8 °F | 3.59 in. |
| February | 6.7 °F | 31.9 °F | 2.64 in. |
| March | 13.9 °F | 40.9 °F | 2.32 in. |
| April | 22.6 °F | 49.2 °F | 2.32 in. |
| May | 31.4 °F | 59.4 °F | 2.86 in. |
| June | 37.6 °F | 68.5 °F | 2.31 in. |
| July | 42.3 °F | 79.4 °F | 1.03 in. |
| August | 40.2 °F | 79.3 °F | 1.09 in. |
| September | 33.0 °F | 69.1 °F | 1.35 in. |
| October | 24.8 °F | 53.1 °F | 1.93 in. |
| November | 14.6 °F | 37.3 °F | 2.45 in. |
| December | 6.2 °F | 27.2 °F | 3.76 in. |
| Annual | 23.2 °F | 51.9 °F | 27.65 in. |
| 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 : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 3b : -35°F to -30°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfc - Subarctic With Cool Summers And Year Around Rainfall |