Willey, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.7 °F (low) to 58.7 °F (high). Annual precipitation averages 33.7 Inches. Willey is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 10.5 °F | 28.2 °F | 0.83 in. |
| February | 14.6 °F | 32.9 °F | 1.09 in. |
| March | 25.4 °F | 46.3 °F | 1.94 in. |
| April | 36.2 °F | 59.9 °F | 3.5 in. |
| May | 48.9 °F | 70.9 °F | 4.76 in. |
| June | 59.6 °F | 81.2 °F | 5.09 in. |
| July | 63.2 °F | 84.0 °F | 4.09 in. |
| August | 60.4 °F | 81.8 °F | 4.02 in. |
| September | 51.1 °F | 76.2 °F | 3.07 in. |
| October | 39.2 °F | 63.2 °F | 2.62 in. |
| November | 26.4 °F | 46.5 °F | 1.47 in. |
| December | 16.3 °F | 33.4 °F | 1.26 in. |
| Annual | 37.7 °F | 58.7 °F | 33.74 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 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 | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |