Port Huron, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 4.6 °C (low) to 13.6 °C (high). Annual precipitation averages 888 Millimeters. Port Huron is located in USDA Plant Hardiness Zone 6b. 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 | -7.6 °C | -0.7 °C | 65.28 mm |
| February | -7.4 °C | 0.3 °C | 52.58 mm |
| March | -3.2 °C | 5.1 °C | 58.93 mm |
| April | 2.3 °C | 11.9 °C | 84.33 mm |
| May | 8.3 °C | 18.6 °C | 89.92 mm |
| June | 13.9 °C | 24.3 °C | 89.15 mm |
| July | 16.9 °C | 26.9 °C | 78.74 mm |
| August | 16.2 °C | 26.2 °C | 77.98 mm |
| September | 12.3 °C | 22.9 °C | 80.77 mm |
| October | 6.6 °C | 15.9 °C | 75.95 mm |
| November | 1.1 °C | 8.8 °C | 70.87 mm |
| December | -3.9 °C | 2.4 °C | 63.5 mm |
| Annual | 4.6 °C | 13.6 °C | 888 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 6b : -20.6°C to -17.8°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 |