Harrison, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.4 °C (low) to 12.8 °C (high). Annual precipitation averages 876.1 Millimeters. Harrison is located in USDA Plant Hardiness Zone 5a. 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 | -11.9 °C | -2.6 °C | 57.4 mm |
| February | -12.3 °C | -0.9 °C | 42.93 mm |
| March | -7.9 °C | 4.9 °C | 55.88 mm |
| April | -1.4 °C | 12 °C | 93.73 mm |
| May | 5.3 °C | 19.4 °C | 93.73 mm |
| June | 10.4 °C | 24.9 °C | 84.84 mm |
| July | 12.6 °C | 27.1 °C | 77.47 mm |
| August | 11.6 °C | 25.9 °C | 87.38 mm |
| September | 7.1 °C | 21.8 °C | 67.82 mm |
| October | 1.7 °C | 14 °C | 93.47 mm |
| November | -3.2 °C | 6.4 °C | 62.74 mm |
| December | -7.8 °C | 0.3 °C | 58.67 mm |
| Annual | 0.4 °C | 12.8 °C | 876.06 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 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |