Brussels, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.8 °C (low) to 11.6 °C (high). Annual precipitation averages 813.6 Millimeters. Brussels is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.1 °C | -3.9 °C | 39.88 mm |
| February | -10.4 °C | -2.3 °C | 29.21 mm |
| March | -5.1 °C | 3.6 °C | 44.7 mm |
| April | 1.1 °C | 10.3 °C | 77.98 mm |
| May | 7.2 °C | 17.5 °C | 86.61 mm |
| June | 12.7 °C | 23.1 °C | 97.54 mm |
| July | 15.7 °C | 25.9 °C | 92.71 mm |
| August | 15.3 °C | 25.3 °C | 86.87 mm |
| September | 11.1 °C | 20.9 °C | 82.04 mm |
| October | 4.8 °C | 13.3 °C | 77.72 mm |
| November | -1.1 °C | 5.9 °C | 53.34 mm |
| December | -7 °C | -0.6 °C | 44.96 mm |
| Annual | 2.8 °C | 11.6 °C | 813.56 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |