Millersburg, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.4 °C (low) to 16.6 °C (high). Annual precipitation averages 1171.2 Millimeters. Millersburg is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.3 °C | 2.7 °C | 80.77 mm |
| February | -5.7 °C | 4.4 °C | 65.53 mm |
| March | -1.5 °C | 9.5 °C | 93.98 mm |
| April | 4.2 °C | 16.8 °C | 97.79 mm |
| May | 9.8 °C | 22.2 °C | 105.66 mm |
| June | 14.9 °C | 26.9 °C | 106.68 mm |
| July | 17.2 °C | 29.4 °C | 112.27 mm |
| August | 16.3 °C | 28.4 °C | 109.47 mm |
| September | 12.3 °C | 24.7 °C | 122.43 mm |
| October | 6.1 °C | 17.9 °C | 105.16 mm |
| November | 0.7 °C | 11.4 °C | 81.28 mm |
| December | -3.3 °C | 5.3 °C | 90.17 mm |
| Annual | 5.4 °C | 16.6 °C | 1171.19 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |