Penn Wynne, Pennsylvania has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 8.5 °C (low) to 17.9 °C (high). Annual precipitation averages 1204.5 Millimeters. Penn Wynne is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 1 - Apr. 10 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.2 °C | 4.8 °C | 88.65 mm |
| February | -2.4 °C | 6.3 °C | 72.14 mm |
| March | 1.3 °C | 10.8 °C | 109.73 mm |
| April | 6.9 °C | 17.4 °C | 92.46 mm |
| May | 12.2 °C | 22.7 °C | 99.82 mm |
| June | 17.6 °C | 27.8 °C | 109.47 mm |
| July | 20.6 °C | 30.3 °C | 113.54 mm |
| August | 19.8 °C | 29.4 °C | 121.67 mm |
| September | 15.9 °C | 25.8 °C | 110.74 mm |
| October | 9.4 °C | 19 °C | 97.79 mm |
| November | 3.8 °C | 12.9 °C | 79.25 mm |
| December | -0.2 °C | 7.4 °C | 109.22 mm |
| Annual | 8.5 °C | 17.9 °C | 1204.48 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Apr. 1 - Apr. 10 |
| Average Days With Frost | 75-100 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |