Donnellson, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42 °F (low) to 62.1 °F (high). Annual precipitation averages 39.1 Inches. Donnellson is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 16.0 °F | 33.0 °F | 1.53 in. |
| February | 19.6 °F | 37.7 °F | 1.88 in. |
| March | 29.9 °F | 50.3 °F | 2.53 in. |
| April | 40.9 °F | 63.3 °F | 3.75 in. |
| May | 52.7 °F | 73.5 °F | 5.11 in. |
| June | 62.3 °F | 82.9 °F | 4.97 in. |
| July | 66.0 °F | 86.6 °F | 4.22 in. |
| August | 63.8 °F | 85.0 °F | 3.84 in. |
| September | 55.3 °F | 78.4 °F | 3.82 in. |
| October | 43.6 °F | 65.4 °F | 3.08 in. |
| November | 32.0 °F | 50.5 °F | 2.47 in. |
| December | 21.9 °F | 38.0 °F | 1.94 in. |
| Annual | 42 °F | 62.1 °F | 39.14 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |