Mackinac Island, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.7 °F (low) to 50.3 °F (high). Annual precipitation averages 31.9 Inches. Mackinac Island is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 12.0 °F | 24.9 °F | 1.93 in. |
| February | 11.4 °F | 26.3 °F | 1.32 in. |
| March | 19.0 °F | 34.7 °F | 1.68 in. |
| April | 30.8 °F | 46.3 °F | 2.66 in. |
| May | 41.5 °F | 58.5 °F | 2.83 in. |
| June | 51.9 °F | 69.0 °F | 2.94 in. |
| July | 58.6 °F | 74.8 °F | 2.9 in. |
| August | 58.5 °F | 74.2 °F | 3.12 in. |
| September | 52.0 °F | 67.2 °F | 3.42 in. |
| October | 40.8 °F | 54.2 °F | 4.18 in. |
| November | 31.3 °F | 41.7 °F | 2.63 in. |
| December | 21.1 °F | 31.7 °F | 2.28 in. |
| Annual | 35.7 °F | 50.3 °F | 31.89 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |