Northport, Michigan has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 3.9 °C (low) to 11.3 °C (high). Annual precipitation averages 819.9 Millimeters. Northport is located in USDA Plant Hardiness Zone 6b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -7.3 °C | -2.1 °C | 57.4 mm |
| February | -7.8 °C | -1.4 °C | 37.85 mm |
| March | -4.9 °C | 3 °C | 50.04 mm |
| April | 0.7 °C | 8.6 °C | 71.88 mm |
| May | 6 °C | 15.4 °C | 73.41 mm |
| June | 11.9 °C | 21.1 °C | 74.93 mm |
| July | 15.8 °C | 23.9 °C | 68.07 mm |
| August | 15.9 °C | 24.1 °C | 67.31 mm |
| September | 12.4 °C | 20.8 °C | 87.63 mm |
| October | 6.4 °C | 13.6 °C | 100.33 mm |
| November | 1.2 °C | 6.9 °C | 73.91 mm |
| December | -3.6 °C | 1.2 °C | 57.15 mm |
| Annual | 3.9 °C | 11.3 °C | 819.91 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 125-150 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 |