Harrisville, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.6 °C (low) to 15.5 °C (high). Annual precipitation averages 1117.9 Millimeters. Harrisville is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -8.2 °C | 1.6 °C | 80.52 mm |
| February | -7.5 °C | 3.3 °C | 64.52 mm |
| March | -3.5 °C | 8.3 °C | 83.06 mm |
| April | 2.3 °C | 15.6 °C | 99.57 mm |
| May | 7.9 °C | 21.3 °C | 100.58 mm |
| June | 12.9 °C | 25.8 °C | 121.41 mm |
| July | 15 °C | 28 °C | 117.6 mm |
| August | 14.2 °C | 27.3 °C | 97.28 mm |
| September | 10.4 °C | 23.8 °C | 101.09 mm |
| October | 4.5 °C | 16.9 °C | 85.6 mm |
| November | -0.4 °C | 10.1 °C | 84.07 mm |
| December | -4.7 °C | 4.1 °C | 82.55 mm |
| Annual | 3.6 °C | 15.5 °C | 1117.85 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |