Parkman, Ohio has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.1 °C (low) to 15 °C (high). Annual precipitation averages 1096.3 Millimeters. Parkman 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 | -7.9 °C | 0.8 °C | 79.5 mm |
| February | -7.4 °C | 2.4 °C | 62.99 mm |
| March | -3.2 °C | 7.4 °C | 85.09 mm |
| April | 2.7 °C | 15 °C | 100.58 mm |
| May | 8.4 °C | 21.1 °C | 104.14 mm |
| June | 13.6 °C | 25.7 °C | 106.68 mm |
| July | 15.7 °C | 27.8 °C | 111 mm |
| August | 14.8 °C | 26.9 °C | 90.93 mm |
| September | 11 °C | 23.4 °C | 100.84 mm |
| October | 5.1 °C | 16.5 °C | 91.44 mm |
| November | 0.1 °C | 9.5 °C | 81.28 mm |
| December | -4.3 °C | 3.4 °C | 81.79 mm |
| Annual | 4.1 °C | 15 °C | 1096.26 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 |