Donnelly, Idaho has a Humid Continental Climate - Dry Cool Summer climate (Köppen classification: Dsb). Average annual temperatures range from 27.4 °F (low) to 55.1 °F (high). Annual precipitation averages 25.4 Inches. Donnelly is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Jun. 1 - Jun. 10 through the first frost around Aug. 21 - Aug. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 11.9 °F | 32.3 °F | 3.06 in. |
| February | 13.6 °F | 36.9 °F | 2.45 in. |
| March | 19.9 °F | 43.8 °F | 2.85 in. |
| April | 26.5 °F | 51.6 °F | 2.47 in. |
| May | 33.9 °F | 61.6 °F | 2.43 in. |
| June | 39.4 °F | 69.7 °F | 1.82 in. |
| July | 44.7 °F | 81.9 °F | 0.53 in. |
| August | 42.9 °F | 81.6 °F | 0.47 in. |
| September | 35.3 °F | 71.7 °F | 0.96 in. |
| October | 27.6 °F | 57.1 °F | 1.83 in. |
| November | 20.6 °F | 41.3 °F | 2.7 in. |
| December | 12.7 °F | 31.6 °F | 3.82 in. |
| Annual | 27.4 °F | 55.1 °F | 25.39 in. |
| Average First Frost Date | Aug. 21 - Aug. 31 |
| Average Last Frost Date | Jun. 1 - Jun. 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dsb - Humid Continental Climate - Dry Cool Summer |