Stewartstown, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 43.9 °F (low) to 63.4 °F (high). Annual precipitation averages 47.9 Inches. Stewartstown 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 23.6 °F | 39.6 °F | 3.48 in. |
| February | 25.0 °F | 42.9 °F | 2.83 in. |
| March | 31.5 °F | 51.6 °F | 4.14 in. |
| April | 41.8 °F | 64.0 °F | 3.82 in. |
| May | 51.3 °F | 72.9 °F | 4.04 in. |
| June | 60.3 °F | 80.6 °F | 4.11 in. |
| July | 64.7 °F | 84.9 °F | 4.65 in. |
| August | 62.9 °F | 83.3 °F | 4.19 in. |
| September | 56.5 °F | 76.9 °F | 5.03 in. |
| October | 45.2 °F | 65.6 °F | 4.34 in. |
| November | 35.7 °F | 54.3 °F | 3.42 in. |
| December | 28.2 °F | 43.8 °F | 3.81 in. |
| Annual | 43.9 °F | 63.4 °F | 47.86 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : 0°F to 5°F |
| Plant Hardiness Zone - 2012 | Zone 7a : 0°F to 5°F |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |