Forestville, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.3 °C (low) to 15.9 °C (high). Annual precipitation averages 1306.6 Millimeters. Forestville is located in USDA Plant Hardiness Zone 6b. 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 | -7.5 °C | 2.2 °C | 92.2 mm |
| February | -6.8 °C | 3.7 °C | 71.12 mm |
| March | -2.4 °C | 8.6 °C | 103.89 mm |
| April | 3.3 °C | 15.6 °C | 107.44 mm |
| May | 8.7 °C | 21.4 °C | 106.43 mm |
| June | 13.7 °C | 25.9 °C | 126.49 mm |
| July | 15.9 °C | 28.7 °C | 126.24 mm |
| August | 14.9 °C | 27.7 °C | 114.05 mm |
| September | 11.1 °C | 23.9 °C | 134.87 mm |
| October | 4.9 °C | 17.3 °C | 125.22 mm |
| November | -0.2 °C | 10.6 °C | 94.49 mm |
| December | -4.3 °C | 4.7 °C | 104.14 mm |
| Annual | 4.3 °C | 15.9 °C | 1306.58 mm |
| 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 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |