Mill Creek, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 40.2 °F (low) to 62.2 °F (high). Annual precipitation averages 40.5 Inches. Mill Creek 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 | 19.9 °F | 37.1 °F | 2.79 in. |
| February | 20.9 °F | 40.2 °F | 2.33 in. |
| March | 27.6 °F | 48.8 °F | 3.38 in. |
| April | 37.4 °F | 62.6 °F | 3.58 in. |
| May | 47.8 °F | 72.8 °F | 3.91 in. |
| June | 57.1 °F | 80.8 °F | 3.99 in. |
| July | 61.2 °F | 85.2 °F | 3.29 in. |
| August | 59.7 °F | 83.6 °F | 3.52 in. |
| September | 52.5 °F | 76.7 °F | 4.01 in. |
| October | 41.1 °F | 64.7 °F | 3.67 in. |
| November | 31.9 °F | 52.7 °F | 2.9 in. |
| December | 25.0 °F | 41.4 °F | 3.16 in. |
| Annual | 40.2 °F | 62.2 °F | 40.53 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 |