Stonerstown, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 39.5 °F (low) to 62.2 °F (high). Annual precipitation averages 40.8 Inches. Stonerstown is located in USDA Plant Hardiness Zone 6b. 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 | 19.4 °F | 37.4 °F | 2.88 in. |
| February | 20.6 °F | 40.7 °F | 2.32 in. |
| March | 27.2 °F | 49.3 °F | 3.49 in. |
| April | 37.0 °F | 62.5 °F | 3.58 in. |
| May | 47.3 °F | 72.4 °F | 3.98 in. |
| June | 56.2 °F | 80.4 °F | 3.68 in. |
| July | 60.6 °F | 84.9 °F | 3.92 in. |
| August | 58.9 °F | 83.3 °F | 3.42 in. |
| September | 51.7 °F | 76.4 °F | 3.92 in. |
| October | 40.1 °F | 64.7 °F | 3.29 in. |
| November | 30.7 °F | 52.6 °F | 3.12 in. |
| December | 24.3 °F | 41.5 °F | 3.17 in. |
| Annual | 39.5 °F | 62.2 °F | 40.77 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 6b : -5°F to 0°F |
| Plant Hardiness Zone - 2012 | Zone 6b : -5°F to 0°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |