De Kalb, Texas has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.2 °C (low) to 24 °C (high). Annual precipitation averages 1278.1 Millimeters. De Kalb is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.3 °C | 12.6 °C | 90.93 mm |
| February | 2.2 °C | 14.8 °C | 110.74 mm |
| March | 6.3 °C | 19.3 °C | 121.92 mm |
| April | 10.4 °C | 23.7 °C | 118.36 mm |
| May | 15.8 °C | 27.7 °C | 138.43 mm |
| June | 20.1 °C | 31.9 °C | 99.06 mm |
| July | 21.9 °C | 34.3 °C | 82.3 mm |
| August | 21.2 °C | 34.6 °C | 74.93 mm |
| September | 17.7 °C | 31.1 °C | 103.12 mm |
| October | 10.9 °C | 25.2 °C | 116.84 mm |
| November | 5.6 °C | 18.6 °C | 102.11 mm |
| December | 1.5 °C | 13.7 °C | 119.38 mm |
| Annual | 11.2 °C | 24 °C | 1278.12 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 8b : -9.4°C to -6.7°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |