Grand Marais, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.4 °C (low) to 10.8 °C (high). Annual precipitation averages 827.8 Millimeters. Grand Marais 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 | -11.7 °C | -3.9 °C | 61.21 mm |
| February | -11.8 °C | -2.6 °C | 42.16 mm |
| March | -8.2 °C | 2.5 °C | 48.77 mm |
| April | -2.3 °C | 9 °C | 68.58 mm |
| May | 3.6 °C | 16.3 °C | 65.02 mm |
| June | 8.8 °C | 21.8 °C | 74.93 mm |
| July | 11.6 °C | 24.1 °C | 74.42 mm |
| August | 12.3 °C | 24.4 °C | 57.91 mm |
| September | 9.3 °C | 20.4 °C | 90.17 mm |
| October | 3.2 °C | 12.7 °C | 105.92 mm |
| November | -2.3 °C | 5.2 °C | 73.66 mm |
| December | -7.9 °C | -0.5 °C | 65.02 mm |
| Annual | 0.4 °C | 10.8 °C | 827.77 mm |
| 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 : -26.1°C to -23.3°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 |