Lewistown, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 41.2 °F (low) to 61.9 °F (high). Annual precipitation averages 42.7 Inches. Lewistown 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 20.6 °F | 36.9 °F | 2.91 in. |
| February | 21.8 °F | 40.2 °F | 2.27 in. |
| March | 28.6 °F | 49.1 °F | 3.47 in. |
| April | 38.6 °F | 62.1 °F | 3.65 in. |
| May | 48.9 °F | 72.2 °F | 4.13 in. |
| June | 58.2 °F | 80.3 °F | 4.0 in. |
| July | 62.4 °F | 84.8 °F | 3.72 in. |
| August | 61.0 °F | 83.1 °F | 3.86 in. |
| September | 53.7 °F | 76.2 °F | 4.44 in. |
| October | 42.3 °F | 64.3 °F | 3.9 in. |
| November | 32.8 °F | 52.4 °F | 3.08 in. |
| December | 25.7 °F | 41.1 °F | 3.3 in. |
| Annual | 41.2 °F | 61.9 °F | 42.73 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |