Port Sanilac, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 39.8 °F (low) to 54.2 °F (high). Annual precipitation averages 33.6 Inches. Port Sanilac is located in USDA Plant Hardiness Zone 6a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 17.7 °F | 29.8 °F | 2.29 in. |
| February | 17.6 °F | 31.6 °F | 1.89 in. |
| March | 25.4 °F | 39.7 °F | 2.06 in. |
| April | 35.2 °F | 50.0 °F | 3.17 in. |
| May | 45.5 °F | 61.3 °F | 3.38 in. |
| June | 55.8 °F | 71.5 °F | 3.26 in. |
| July | 62.2 °F | 77.5 °F | 3.04 in. |
| August | 61.4 °F | 77.2 °F | 3.27 in. |
| September | 54.8 °F | 71.6 °F | 3.2 in. |
| October | 43.8 °F | 59.0 °F | 3.06 in. |
| November | 33.5 °F | 46.2 °F | 2.6 in. |
| December | 24.5 °F | 35.5 °F | 2.33 in. |
| Annual | 39.8 °F | 54.2 °F | 33.55 in. |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Dfb - Humid Continental Mild Summer, Wet All Year |