Harrison, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 32.6 °F (low) to 55 °F (high). Annual precipitation averages 34.5 Inches. 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 | 10.5 °F | 27.3 °F | 2.26 in. |
| February | 9.9 °F | 30.4 °F | 1.69 in. |
| March | 17.7 °F | 40.8 °F | 2.2 in. |
| April | 29.5 °F | 53.6 °F | 3.69 in. |
| May | 41.5 °F | 67.0 °F | 3.69 in. |
| June | 50.8 °F | 76.8 °F | 3.34 in. |
| July | 54.6 °F | 80.7 °F | 3.05 in. |
| August | 52.8 °F | 78.7 °F | 3.44 in. |
| September | 44.7 °F | 71.2 °F | 2.67 in. |
| October | 35.0 °F | 57.2 °F | 3.68 in. |
| November | 26.3 °F | 43.6 °F | 2.47 in. |
| December | 17.9 °F | 32.5 °F | 2.31 in. |
| Annual | 32.6 °F | 55 °F | 34.49 in. |
| 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 : -20°F to -15°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |