Butternut, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.3 °C (low) to 10.5 °C (high). Annual precipitation averages 871.7 Millimeters. Butternut is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -17.1 °C | -6.4 °C | 29.97 mm |
| February | -15.9 °C | -3.5 °C | 26.42 mm |
| March | -9.8 °C | 2.9 °C | 42.93 mm |
| April | -2.3 °C | 10.3 °C | 75.18 mm |
| May | 4.8 °C | 18.1 °C | 101.6 mm |
| June | 10.3 °C | 23.1 °C | 125.73 mm |
| July | 12.9 °C | 25.4 °C | 108.71 mm |
| August | 11.4 °C | 24.3 °C | 95.5 mm |
| September | 7.4 °C | 19.9 °C | 93.47 mm |
| October | 0.9 °C | 11.8 °C | 85.6 mm |
| November | -5.7 °C | 3.2 °C | 50.04 mm |
| December | -12.6 °C | -3.6 °C | 36.58 mm |
| Annual | -1.3 °C | 10.5 °C | 871.73 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |