Millersburg, Indiana has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 4.7 °C (low) to 15 °C (high). Annual precipitation averages 958.6 Millimeters. Millersburg is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.2 °C | -0.3 °C | 57.91 mm |
| February | -7.2 °C | 1.7 °C | 52.83 mm |
| March | -2.5 °C | 7.9 °C | 55.63 mm |
| April | 3.5 °C | 15 °C | 91.44 mm |
| May | 9.9 °C | 21.2 °C | 111.25 mm |
| June | 15.2 °C | 26.4 °C | 98.81 mm |
| July | 16.9 °C | 28.2 °C | 98.81 mm |
| August | 15.8 °C | 27.2 °C | 100.08 mm |
| September | 11.8 °C | 23.9 °C | 78.49 mm |
| October | 5.7 °C | 16.9 °C | 83.06 mm |
| November | 0.1 °C | 9.1 °C | 72.64 mm |
| December | -4.9 °C | 2.4 °C | 57.66 mm |
| Annual | 4.7 °C | 15 °C | 958.61 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |