Harrison, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.6 °C (low) to 12.6 °C (high). Annual precipitation averages 837.9 Millimeters. Harrison 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 | -12 °C | -3.7 °C | 34.8 mm |
| February | -10.8 °C | -1.8 °C | 28.7 mm |
| March | -5.1 °C | 4.6 °C | 47.24 mm |
| April | 1.4 °C | 12.1 °C | 81.53 mm |
| May | 8.1 °C | 19.3 °C | 93.22 mm |
| June | 13.8 °C | 24.7 °C | 117.09 mm |
| July | 16.2 °C | 27.2 °C | 96.01 mm |
| August | 15.2 °C | 26.1 °C | 91.44 mm |
| September | 10.8 °C | 22.1 °C | 82.04 mm |
| October | 4.2 °C | 14.4 °C | 72.14 mm |
| November | -2.1 °C | 6.5 °C | 50.29 mm |
| December | -8.2 °C | -0.6 °C | 43.43 mm |
| Annual | 2.6 °C | 12.6 °C | 837.93 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 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |