Sumner, 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 17.7 °C (high). Annual precipitation averages 1040.9 Millimeters. Sumner 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 | -8.5 °C | 2.5 °C | 33.78 mm |
| February | -5.9 °C | 5.3 °C | 45.21 mm |
| March | -0.3 °C | 11.8 °C | 66.8 mm |
| April | 5.6 °C | 17.9 °C | 100.33 mm |
| May | 11.7 °C | 23.3 °C | 136.91 mm |
| June | 17.4 °C | 28.3 °C | 134.62 mm |
| July | 19.4 °C | 30.6 °C | 123.7 mm |
| August | 17.9 °C | 29.8 °C | 106.17 mm |
| September | 12.7 °C | 26.4 °C | 108.2 mm |
| October | 6.4 °C | 19.6 °C | 82.04 mm |
| November | 0.1 °C | 11.8 °C | 59.18 mm |
| December | -5.6 °C | 4.8 °C | 43.94 mm |
| Annual | 5.9 °C | 17.7 °C | 1040.88 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 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |