Hawthorn, Pennsylvania has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.7 °C (low) to 15.8 °C (high). Annual precipitation averages 1163.3 Millimeters. Hawthorn is located in USDA Plant Hardiness Zone 6a. 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 | -7.6 °C | 1.8 °C | 91.19 mm |
| February | -7.3 °C | 3.4 °C | 66.8 mm |
| March | -3.5 °C | 8.6 °C | 91.44 mm |
| April | 1.9 °C | 16.3 °C | 100.58 mm |
| May | 7.8 °C | 22.2 °C | 101.09 mm |
| June | 13 °C | 26.1 °C | 119.89 mm |
| July | 15.2 °C | 28.2 °C | 118.11 mm |
| August | 14.5 °C | 27.8 °C | 104.65 mm |
| September | 10.6 °C | 23.9 °C | 103.63 mm |
| October | 4.4 °C | 17.2 °C | 84.07 mm |
| November | -0.6 °C | 10.2 °C | 91.19 mm |
| December | -4.4 °C | 4.2 °C | 90.68 mm |
| Annual | 3.7 °C | 15.8 °C | 1163.32 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 6a : -23.3°C to -20.6°C |
| Plant Hardiness Zone - 2012 | Zone 6a : -23.3°C to -20.6°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |