Millersburg, Ohio has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 40 °F (low) to 60.8 °F (high). Annual precipitation averages 40.8 Inches. Millersburg 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 18.7 °F | 35.1 °F | 2.94 in. |
| February | 19.9 °F | 38.2 °F | 2.26 in. |
| March | 27.7 °F | 48.0 °F | 3.19 in. |
| April | 37.9 °F | 61.4 °F | 3.84 in. |
| May | 48.6 °F | 71.4 °F | 4.05 in. |
| June | 57.5 °F | 79.9 °F | 4.96 in. |
| July | 61.2 °F | 83.2 °F | 4.09 in. |
| August | 59.4 °F | 82.0 °F | 3.39 in. |
| September | 52.0 °F | 75.8 °F | 3.15 in. |
| October | 40.8 °F | 63.8 °F | 3.1 in. |
| November | 31.7 °F | 51.0 °F | 2.89 in. |
| December | 24.3 °F | 39.9 °F | 2.96 in. |
| Annual | 40 °F | 60.8 °F | 40.82 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |