Hamilton, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.4 °C (low) to 17.3 °C (high). Annual precipitation averages 1013.7 Millimeters. Hamilton is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.7 °C | 1.8 °C | 28.19 mm |
| February | -6.7 °C | 4.8 °C | 40.39 mm |
| March | -0.9 °C | 11.5 °C | 68.07 mm |
| April | 4.4 °C | 17.6 °C | 99.57 mm |
| May | 11.1 °C | 22.9 °C | 148.08 mm |
| June | 16.4 °C | 28.1 °C | 132.59 mm |
| July | 18.8 °C | 30.7 °C | 102.87 mm |
| August | 17.7 °C | 29.9 °C | 109.98 mm |
| September | 12.6 °C | 25.6 °C | 106.43 mm |
| October | 6 °C | 19 °C | 82.8 mm |
| November | -0.3 °C | 11.3 °C | 53.34 mm |
| December | -5.9 °C | 4.3 °C | 41.4 mm |
| Annual | 5.4 °C | 17.3 °C | 1013.71 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°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 |