Copper Harbor, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.8 °C (low) to 9.2 °C (high). Annual precipitation averages 815.1 Millimeters. Copper Harbor 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 | -9.9 °C | -4.3 °C | 63.75 mm |
| February | -10.3 °C | -3.4 °C | 47.5 mm |
| March | -6.6 °C | 1.1 °C | 48.01 mm |
| April | -0.8 °C | 6.7 °C | 65.28 mm |
| May | 4.5 °C | 13.9 °C | 71.12 mm |
| June | 8.8 °C | 18.8 °C | 68.33 mm |
| July | 13.2 °C | 22 °C | 61.72 mm |
| August | 14.3 °C | 22.2 °C | 63.5 mm |
| September | 10.8 °C | 18.4 °C | 74.42 mm |
| October | 4.6 °C | 11.1 °C | 93.22 mm |
| November | -1.3 °C | 4.5 °C | 76.96 mm |
| December | -6.2 °C | -0.9 °C | 81.28 mm |
| Annual | 1.8 °C | 9.2 °C | 815.09 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 5b : -26.1°C to -23.3°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |