Millersburg, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.8 °C (low) to 12.3 °C (high). Annual precipitation averages 812 Millimeters. Millersburg 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 | -11.6 °C | -3 °C | 50.55 mm |
| February | -12.3 °C | -1.6 °C | 36.83 mm |
| March | -8.2 °C | 3.9 °C | 44.45 mm |
| April | -1.4 °C | 10.9 °C | 73.15 mm |
| May | 5 °C | 18.8 °C | 76.96 mm |
| June | 10.3 °C | 24.2 °C | 75.95 mm |
| July | 13.1 °C | 26.5 °C | 79.5 mm |
| August | 12.3 °C | 25.8 °C | 84.07 mm |
| September | 8.3 °C | 21.8 °C | 80.26 mm |
| October | 2.8 °C | 13.9 °C | 90.93 mm |
| November | -2.1 °C | 6.3 °C | 63.25 mm |
| December | -7.2 °C | 0.2 °C | 56.13 mm |
| Annual | 0.8 °C | 12.3 °C | 812.03 mm |
| 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 : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |