Brussels, Illinois has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 46 °F (low) to 65.7 °F (high). Annual precipitation averages 41.6 Inches. Brussels 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 22.3 °F | 38.9 °F | 2.36 in. |
| February | 25.6 °F | 44.5 °F | 2.19 in. |
| March | 34.4 °F | 55.0 °F | 3.21 in. |
| April | 45.2 °F | 66.8 °F | 4.48 in. |
| May | 56.0 °F | 75.9 °F | 4.91 in. |
| June | 65.1 °F | 84.5 °F | 4.55 in. |
| July | 68.7 °F | 87.9 °F | 3.87 in. |
| August | 66.7 °F | 86.9 °F | 3.59 in. |
| September | 58.2 °F | 80.4 °F | 3.32 in. |
| October | 46.7 °F | 68.6 °F | 3.23 in. |
| November | 35.7 °F | 54.9 °F | 3.33 in. |
| December | 26.9 °F | 43.7 °F | 2.58 in. |
| Annual | 46 °F | 65.7 °F | 41.62 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| 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 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |