Ortonville, Michigan has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 38.4 °F (low) to 56.8 °F (high). Annual precipitation averages 32.9 Inches. 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 | 15.5 °F | 29.7 °F | 2.14 in. |
| February | 16.1 °F | 32.7 °F | 1.7 in. |
| March | 24.4 °F | 42.7 °F | 2.02 in. |
| April | 35.5 °F | 55.8 °F | 3.11 in. |
| May | 47.0 °F | 67.9 °F | 3.79 in. |
| June | 56.6 °F | 77.2 °F | 3.39 in. |
| July | 60.4 °F | 81.1 °F | 3.47 in. |
| August | 59.3 °F | 79.3 °F | 3.14 in. |
| September | 52.0 °F | 73.2 °F | 2.93 in. |
| October | 40.9 °F | 59.8 °F | 2.81 in. |
| November | 31.2 °F | 46.7 °F | 2.33 in. |
| December | 22.3 °F | 34.9 °F | 2.06 in. |
| Annual | 38.4 °F | 56.8 °F | 32.89 in. |
| 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 : -10°F to -5°F |
| Plant Hardiness Zone - 2012 | Zone 6a : -10°F to -5°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |