Hillsdale, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 38.9 °F (low) to 57.5 °F (high). Annual precipitation averages 38.6 Inches. 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 | 16.3 °F | 30.3 °F | 2.54 in. |
| February | 17.3 °F | 33.4 °F | 2.15 in. |
| March | 25.3 °F | 43.6 °F | 2.46 in. |
| April | 36.4 °F | 56.9 °F | 3.68 in. |
| May | 48.4 °F | 68.9 °F | 4.28 in. |
| June | 57.8 °F | 78.0 °F | 3.91 in. |
| July | 60.8 °F | 81.8 °F | 3.63 in. |
| August | 59.0 °F | 79.6 °F | 3.85 in. |
| September | 51.7 °F | 73.7 °F | 3.51 in. |
| October | 40.7 °F | 60.9 °F | 3.34 in. |
| November | 30.8 °F | 47.1 °F | 2.91 in. |
| December | 22.7 °F | 35.2 °F | 2.38 in. |
| Annual | 38.9 °F | 57.5 °F | 38.64 in. |
| 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 : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |