Du Bois, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 45.6 °F (low) to 65.5 °F (high). Annual precipitation averages 45.5 Inches. Du Bois is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 22.8 °F | 39.3 °F | 2.96 in. |
| February | 26.1 °F | 44.2 °F | 2.67 in. |
| March | 34.8 °F | 54.5 °F | 3.83 in. |
| April | 45.1 °F | 66.4 °F | 4.92 in. |
| May | 55.7 °F | 75.6 °F | 5.12 in. |
| June | 64.4 °F | 84.5 °F | 4.86 in. |
| July | 67.7 °F | 87.4 °F | 4.14 in. |
| August | 65.4 °F | 86.5 °F | 3.24 in. |
| September | 57.2 °F | 80.4 °F | 3.31 in. |
| October | 45.8 °F | 69.0 °F | 3.36 in. |
| November | 35.5 °F | 54.8 °F | 4.01 in. |
| December | 27.2 °F | 43.4 °F | 3.08 in. |
| Annual | 45.6 °F | 65.5 °F | 45.5 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |