Millerstown, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 42.1 °F (low) to 62.3 °F (high). Annual precipitation averages 45 Inches. Millerstown is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 21.1 °F | 37.2 °F | 3.16 in. |
| February | 22.1 °F | 40.4 °F | 2.57 in. |
| March | 29.4 °F | 49.6 °F | 3.65 in. |
| April | 39.6 °F | 62.9 °F | 3.7 in. |
| May | 49.9 °F | 72.4 °F | 4.1 in. |
| June | 59.3 °F | 81.0 °F | 4.05 in. |
| July | 63.5 °F | 85.5 °F | 4.23 in. |
| August | 62.0 °F | 83.6 °F | 4.09 in. |
| September | 54.6 °F | 76.6 °F | 4.64 in. |
| October | 43.3 °F | 64.4 °F | 4.08 in. |
| November | 33.5 °F | 52.9 °F | 3.2 in. |
| December | 26.3 °F | 41.6 °F | 3.56 in. |
| Annual | 42.1 °F | 62.3 °F | 45.03 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |