Plainfield, Pennsylvania has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 6.1 °C (low) to 17.3 °C (high). Annual precipitation averages 1128 Millimeters. Plainfield is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -5.6 °C | 3.4 °C | 80.52 mm |
| February | -4.8 °C | 5.2 °C | 65.02 mm |
| March | -0.8 °C | 10.2 °C | 94.23 mm |
| April | 4.8 °C | 17.3 °C | 95.76 mm |
| May | 10.5 °C | 22.7 °C | 109.73 mm |
| June | 15.6 °C | 27.6 °C | 103.63 mm |
| July | 18.1 °C | 30.2 °C | 106.17 mm |
| August | 17.2 °C | 29.1 °C | 93.47 mm |
| September | 13.1 °C | 25.2 °C | 113.79 mm |
| October | 6.7 °C | 18.6 °C | 101.35 mm |
| November | 1.2 °C | 12 °C | 77.98 mm |
| December | -2.9 °C | 5.7 °C | 86.36 mm |
| Annual | 6.1 °C | 17.3 °C | 1128.01 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |