Chillicothe, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.9 °C (low) to 17.6 °C (high). Annual precipitation averages 1041.4 Millimeters. Chillicothe 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 | -8.4 °C | 1.9 °C | 32.77 mm |
| February | -6.2 °C | 5 °C | 45.21 mm |
| March | -0.6 °C | 11.6 °C | 70.1 mm |
| April | 5.4 °C | 17.9 °C | 96.27 mm |
| May | 11.7 °C | 23.3 °C | 138.94 mm |
| June | 17.2 °C | 28.6 °C | 130.3 mm |
| July | 19.4 °C | 30.9 °C | 120.14 mm |
| August | 18.1 °C | 30.1 °C | 113.79 mm |
| September | 13.1 °C | 26.2 °C | 111.51 mm |
| October | 6.3 °C | 19.3 °C | 81.53 mm |
| November | -0.1 °C | 11.5 °C | 58.93 mm |
| December | -5.6 °C | 4.6 °C | 41.91 mm |
| Annual | 5.9 °C | 17.6 °C | 1041.4 mm |
| 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 : -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 |