Spillville, Iowa has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 35.5 °F (low) to 56 °F (high). Annual precipitation averages 37.5 Inches. Spillville is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.6 °F | 24.9 °F | 1.04 in. |
| February | 11.2 °F | 29.2 °F | 1.1 in. |
| March | 23.3 °F | 42.2 °F | 1.96 in. |
| April | 34.6 °F | 57.3 °F | 3.92 in. |
| May | 46.6 °F | 69.1 °F | 4.67 in. |
| June | 57.1 °F | 78.6 °F | 6.05 in. |
| July | 60.5 °F | 81.9 °F | 4.66 in. |
| August | 58.0 °F | 79.9 °F | 4.26 in. |
| September | 49.6 °F | 73.6 °F | 3.76 in. |
| October | 37.5 °F | 60.4 °F | 2.79 in. |
| November | 25.6 °F | 43.9 °F | 1.84 in. |
| December | 14.6 °F | 30.6 °F | 1.43 in. |
| Annual | 35.5 °F | 56 °F | 37.48 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |