Plainfield, Ohio has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 5.1 °C (low) to 16.9 °C (high). Annual precipitation averages 1069.1 Millimeters. Plainfield 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. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -6.6 °C | 2.8 °C | 80.01 mm |
| February | -5.7 °C | 4.6 °C | 59.69 mm |
| March | -1.6 °C | 10.1 °C | 86.36 mm |
| April | 4 °C | 17.6 °C | 99.06 mm |
| May | 9.8 °C | 22.7 °C | 105.41 mm |
| June | 14.7 °C | 27.1 °C | 123.44 mm |
| July | 16.9 °C | 29 °C | 105.66 mm |
| August | 16 °C | 28.4 °C | 98.3 mm |
| September | 11.7 °C | 24.9 °C | 84.07 mm |
| October | 5.3 °C | 18.4 °C | 75.95 mm |
| November | 0.1 °C | 11.4 °C | 74.93 mm |
| December | -3.7 °C | 5.3 °C | 76.2 mm |
| Annual | 5.1 °C | 16.9 °C | 1069.08 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| 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 |