Vassar, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3 °C (low) to 13.8 °C (high). Annual precipitation averages 843.8 Millimeters. Vassar 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 | -9.5 °C | -1.3 °C | 51.05 mm |
| February | -9.4 °C | 0.2 °C | 42.16 mm |
| March | -4.8 °C | 5.7 °C | 49.53 mm |
| April | 1.2 °C | 13.1 °C | 86.11 mm |
| May | 7.6 °C | 20.1 °C | 90.93 mm |
| June | 13 °C | 25.4 °C | 87.63 mm |
| July | 15.2 °C | 27.6 °C | 87.88 mm |
| August | 14.3 °C | 26.3 °C | 84.07 mm |
| September | 9.9 °C | 22.9 °C | 72.14 mm |
| October | 4.3 °C | 15.7 °C | 79.25 mm |
| November | -0.8 °C | 8 °C | 63.75 mm |
| December | -5.5 °C | 1.6 °C | 49.28 mm |
| Annual | 3 °C | 13.8 °C | 843.78 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 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |