Clarksville, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.4 °C (low) to 17.4 °C (high). Annual precipitation averages 1070.9 Millimeters. Clarksville is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.9 °C | 3.8 °C | 81.03 mm |
| February | -5.3 °C | 5.4 °C | 69.09 mm |
| March | -1.4 °C | 10.7 °C | 87.38 mm |
| April | 3.8 °C | 17.9 °C | 86.87 mm |
| May | 9.7 °C | 23.1 °C | 110.49 mm |
| June | 14.7 °C | 27.2 °C | 111.25 mm |
| July | 16.9 °C | 29.3 °C | 115.57 mm |
| August | 16.2 °C | 28.8 °C | 96.27 mm |
| September | 12.3 °C | 25.4 °C | 83.82 mm |
| October | 5.8 °C | 18.8 °C | 71.88 mm |
| November | 0.5 °C | 11.8 °C | 76.45 mm |
| December | -3.1 °C | 6.1 °C | 80.77 mm |
| Annual | 5.4 °C | 17.4 °C | 1070.87 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |