Harwick, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.2 °C (low) to 16.4 °C (high). Annual precipitation averages 1098.8 Millimeters. Harwick 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. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.4 °C | 2.6 °C | 88.65 mm |
| February | -5.8 °C | 4.2 °C | 67.82 mm |
| March | -1.9 °C | 9.3 °C | 83.31 mm |
| April | 3.8 °C | 16.9 °C | 90.17 mm |
| May | 9.8 °C | 22.3 °C | 101.09 mm |
| June | 14.7 °C | 26.7 °C | 114.3 mm |
| July | 16.8 °C | 28.7 °C | 112.52 mm |
| August | 16.1 °C | 28 °C | 93.98 mm |
| September | 12.3 °C | 24.5 °C | 98.04 mm |
| October | 5.9 °C | 17.7 °C | 82.04 mm |
| November | 0.6 °C | 10.8 °C | 80.77 mm |
| December | -3.4 °C | 5 °C | 86.11 mm |
| Annual | 5.2 °C | 16.4 °C | 1098.8 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| 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 | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |