Hillsdale, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.8 °C (low) to 14.2 °C (high). Annual precipitation averages 981.4 Millimeters. Hillsdale is located in USDA Plant Hardiness Zone 6a. 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 | -8.7 °C | -0.9 °C | 64.52 mm |
| February | -8.2 °C | 0.8 °C | 54.61 mm |
| March | -3.7 °C | 6.4 °C | 62.48 mm |
| April | 2.4 °C | 13.8 °C | 93.47 mm |
| May | 9.1 °C | 20.5 °C | 108.71 mm |
| June | 14.3 °C | 25.6 °C | 99.31 mm |
| July | 16 °C | 27.7 °C | 92.2 mm |
| August | 15 °C | 26.4 °C | 97.79 mm |
| September | 10.9 °C | 23.2 °C | 89.15 mm |
| October | 4.8 °C | 16.1 °C | 84.84 mm |
| November | -0.7 °C | 8.4 °C | 73.91 mm |
| December | -5.2 °C | 1.8 °C | 60.45 mm |
| Annual | 3.8 °C | 14.2 °C | 981.44 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 6a : -23.3°C to -20.6°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 |