Middlefield, Ohio has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4 °C (low) to 14.7 °C (high). Annual precipitation averages 1120.4 Millimeters. Middlefield 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 | -8.1 °C | 0.6 °C | 82.3 mm |
| February | -7.7 °C | 2.1 °C | 62.23 mm |
| March | -3.4 °C | 7.2 °C | 84.07 mm |
| April | 2.7 °C | 14.5 °C | 100.58 mm |
| May | 8.6 °C | 20.6 °C | 103.38 mm |
| June | 13.6 °C | 25.3 °C | 109.47 mm |
| July | 15.7 °C | 27.3 °C | 114.55 mm |
| August | 14.8 °C | 26.6 °C | 93.98 mm |
| September | 11 °C | 23.1 °C | 104.39 mm |
| October | 5.2 °C | 16.2 °C | 96.27 mm |
| November | 0.1 °C | 9.3 °C | 84.58 mm |
| December | -4.4 °C | 3.3 °C | 84.58 mm |
| Annual | 4 °C | 14.7 °C | 1120.38 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 |