Harvey, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.3 °C (low) to 10 °C (high). Annual precipitation averages 807.7 Millimeters. Harvey 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -11.4 °C | -3.9 °C | 47.24 mm |
| February | -11.6 °C | -2.7 °C | 39.12 mm |
| March | -7.1 °C | 2.2 °C | 44.45 mm |
| April | -1 °C | 7.5 °C | 66.8 mm |
| May | 4.6 °C | 14.7 °C | 81.03 mm |
| June | 9.8 °C | 20.2 °C | 75.69 mm |
| July | 13.9 °C | 23.4 °C | 81.28 mm |
| August | 13.8 °C | 23.2 °C | 68.33 mm |
| September | 9.9 °C | 19.5 °C | 94.74 mm |
| October | 3.8 °C | 12.1 °C | 99.06 mm |
| November | -1.9 °C | 4.9 °C | 60.2 mm |
| December | -7.6 °C | -0.9 °C | 49.78 mm |
| Annual | 1.3 °C | 10 °C | 807.72 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| 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 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |