Middletown, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.3 °C (low) to 14.2 °C (high). Annual precipitation averages 858.5 Millimeters. Middletown 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. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.2 °C | -0.9 °C | 55.37 mm |
| February | -8.8 °C | 0.6 °C | 42.67 mm |
| March | -4.4 °C | 6.3 °C | 50.04 mm |
| April | 1.7 °C | 13.6 °C | 87.12 mm |
| May | 8 °C | 20.4 °C | 102.62 mm |
| June | 13.4 °C | 25.7 °C | 87.12 mm |
| July | 15.3 °C | 27.8 °C | 84.84 mm |
| August | 14.6 °C | 26.7 °C | 82.04 mm |
| September | 10.3 °C | 23.3 °C | 72.64 mm |
| October | 4.5 °C | 16 °C | 80.26 mm |
| November | -0.7 °C | 8.4 °C | 62.23 mm |
| December | -5.4 °C | 2 °C | 51.56 mm |
| Annual | 3.3 °C | 14.2 °C | 858.51 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| 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 |