De Kalb, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.6 °C (low) to 17.8 °C (high). Annual precipitation averages 972.8 Millimeters. De Kalb is located in USDA Plant Hardiness Zone 6b. 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 | -7.6 °C | 2.8 °C | 26.16 mm |
| February | -5.4 °C | 5.6 °C | 35.05 mm |
| March | 0 °C | 12.1 °C | 56.64 mm |
| April | 5.9 °C | 18.2 °C | 95.25 mm |
| May | 12.2 °C | 23.5 °C | 133.35 mm |
| June | 17.7 °C | 28.6 °C | 129.29 mm |
| July | 20.2 °C | 30.8 °C | 124.46 mm |
| August | 18.9 °C | 30.3 °C | 105.16 mm |
| September | 13.7 °C | 25.9 °C | 96.77 mm |
| October | 7.2 °C | 19.4 °C | 81.28 mm |
| November | 0.6 °C | 11.7 °C | 50.29 mm |
| December | -4.8 °C | 5 °C | 39.12 mm |
| Annual | 6.6 °C | 17.8 °C | 972.82 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |