Dunbar, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.8 °C (low) to 11.4 °C (high). Annual precipitation averages 796.8 Millimeters. Dunbar is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 21 - May 31 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -15.4 °C | -4.8 °C | 31.75 mm |
| February | -14.7 °C | -2.4 °C | 28.45 mm |
| March | -9.1 °C | 3.7 °C | 42.42 mm |
| April | -2.1 °C | 10.8 °C | 69.09 mm |
| May | 4.7 °C | 18.7 °C | 85.09 mm |
| June | 10.3 °C | 23.7 °C | 102.36 mm |
| July | 12.6 °C | 26.1 °C | 94.49 mm |
| August | 11.7 °C | 24.9 °C | 79.25 mm |
| September | 7.4 °C | 20.5 °C | 91.19 mm |
| October | 1.1 °C | 12.8 °C | 83.06 mm |
| November | -4.7 °C | 4.7 °C | 49.02 mm |
| December | -11.2 °C | -1.9 °C | 40.64 mm |
| Annual | -0.8 °C | 11.4 °C | 796.81 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 21 - May 31 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |