Fitchburg, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.1 °C (low) to 13.6 °C (high). Annual precipitation averages 980.2 Millimeters. Fitchburg 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 | -11.7 °C | -2.8 °C | 38.86 mm |
| February | -9.8 °C | -0.6 °C | 40.39 mm |
| March | -4.2 °C | 6.1 °C | 54.86 mm |
| April | 2.2 °C | 13.7 °C | 98.55 mm |
| May | 8.8 °C | 20.4 °C | 113.79 mm |
| June | 14.2 °C | 25.6 °C | 143.76 mm |
| July | 16.6 °C | 27.6 °C | 114.05 mm |
| August | 15.6 °C | 26.7 °C | 108.97 mm |
| September | 10.8 °C | 22.8 °C | 91.44 mm |
| October | 4.4 °C | 15.8 °C | 73.91 mm |
| November | -2.1 °C | 7.1 °C | 57.4 mm |
| December | -7.9 °C | 0.3 °C | 44.2 mm |
| Annual | 3.1 °C | 13.6 °C | 980.18 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |