Ortonville, Michigan has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 3.6 °C (low) to 13.7 °C (high). Annual precipitation averages 835.4 Millimeters. Ortonville 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 | -1.3 °C | 54.36 mm |
| February | -8.8 °C | 0.4 °C | 43.18 mm |
| March | -4.2 °C | 5.9 °C | 51.31 mm |
| April | 1.9 °C | 13.2 °C | 78.99 mm |
| May | 8.3 °C | 19.9 °C | 96.27 mm |
| June | 13.7 °C | 25.1 °C | 86.11 mm |
| July | 15.8 °C | 27.3 °C | 88.14 mm |
| August | 15.2 °C | 26.3 °C | 79.76 mm |
| September | 11.1 °C | 22.9 °C | 74.42 mm |
| October | 4.9 °C | 15.4 °C | 71.37 mm |
| November | -0.4 °C | 8.2 °C | 59.18 mm |
| December | -5.4 °C | 1.6 °C | 52.32 mm |
| Annual | 3.6 °C | 13.7 °C | 835.41 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |