Zionsville, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.3 °C (low) to 16.6 °C (high). Annual precipitation averages 1100.1 Millimeters. Zionsville 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.7 °C | 1.8 °C | 74.68 mm |
| February | -5.2 °C | 4 °C | 62.99 mm |
| March | -0.3 °C | 10 °C | 83.31 mm |
| April | 5.7 °C | 17.1 °C | 112.52 mm |
| May | 11.8 °C | 22.7 °C | 119.13 mm |
| June | 16.8 °C | 27.3 °C | 131.57 mm |
| July | 18.5 °C | 29 °C | 108.97 mm |
| August | 17.6 °C | 28.4 °C | 79.25 mm |
| September | 13.3 °C | 25.4 °C | 84.58 mm |
| October | 6.9 °C | 18.6 °C | 80.77 mm |
| November | 1.1 °C | 10.7 °C | 86.87 mm |
| December | -3.8 °C | 4.2 °C | 75.44 mm |
| Annual | 6.3 °C | 16.6 °C | 1100.08 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |