De Kalb, Missouri has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 43.8 °F (low) to 64.1 °F (high). Annual precipitation averages 38.3 Inches. 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 | 18.3 °F | 37.0 °F | 1.03 in. |
| February | 22.2 °F | 42.0 °F | 1.38 in. |
| March | 32.0 °F | 53.8 °F | 2.23 in. |
| April | 42.6 °F | 64.7 °F | 3.75 in. |
| May | 53.9 °F | 74.3 °F | 5.25 in. |
| June | 63.8 °F | 83.5 °F | 5.09 in. |
| July | 68.3 °F | 87.4 °F | 4.9 in. |
| August | 66.0 °F | 86.5 °F | 4.14 in. |
| September | 56.6 °F | 78.6 °F | 3.81 in. |
| October | 44.9 °F | 67.0 °F | 3.2 in. |
| November | 33.1 °F | 53.0 °F | 1.98 in. |
| December | 23.3 °F | 41.0 °F | 1.54 in. |
| Annual | 43.8 °F | 64.1 °F | 38.3 in. |
| 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 : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |