Millheim, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.3 °F (low) to 59.4 °F (high). Annual precipitation averages 42.3 Inches. Millheim is located in USDA Plant Hardiness Zone 6b. 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 | 17.2 °F | 33.6 °F | 2.93 in. |
| February | 18.6 °F | 37.0 °F | 2.31 in. |
| March | 25.6 °F | 46.0 °F | 3.22 in. |
| April | 36.1 °F | 59.8 °F | 3.6 in. |
| May | 46.5 °F | 70.7 °F | 3.93 in. |
| June | 55.6 °F | 78.7 °F | 4.09 in. |
| July | 59.5 °F | 82.9 °F | 4.1 in. |
| August | 57.5 °F | 81.1 °F | 3.88 in. |
| September | 50.2 °F | 73.7 °F | 4.19 in. |
| October | 39.3 °F | 61.6 °F | 3.72 in. |
| November | 30.1 °F | 49.4 °F | 3.11 in. |
| December | 22.9 °F | 38.1 °F | 3.25 in. |
| Annual | 38.3 °F | 59.4 °F | 42.33 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 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |