Birchwood, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.5 °C (low) to 11.4 °C (high). Annual precipitation averages 880.6 Millimeters. Birchwood is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep.1 - Sep. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -16.6 °C | -5.8 °C | 26.67 mm |
| February | -15.2 °C | -2.9 °C | 27.69 mm |
| March | -8.3 °C | 3.9 °C | 43.69 mm |
| April | -1.1 °C | 11.7 °C | 77.98 mm |
| May | 5.6 °C | 19.1 °C | 103.12 mm |
| June | 11.2 °C | 24.1 °C | 117.35 mm |
| July | 13.6 °C | 26.3 °C | 110.49 mm |
| August | 12.3 °C | 25.2 °C | 104.39 mm |
| September | 8.1 °C | 20.8 °C | 97.79 mm |
| October | 1.6 °C | 13 °C | 86.11 mm |
| November | -5.1 °C | 4.3 °C | 49.02 mm |
| December | -12.1 °C | -2.9 °C | 36.32 mm |
| Annual | -0.5 °C | 11.4 °C | 880.62 mm |
| Average First Frost Date | Sep.1 - Sep. 10 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |