Northport, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.9 °C (low) to 12.8 °C (high). Annual precipitation averages 860 Millimeters. Northport is located in USDA Plant Hardiness Zone 5a. 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 | -12.8 °C | -3.7 °C | 34.29 mm |
| February | -11.7 °C | -1.5 °C | 30.23 mm |
| March | -5.8 °C | 4.9 °C | 48.26 mm |
| April | 0.8 °C | 12.7 °C | 82.8 mm |
| May | 7.6 °C | 19.7 °C | 98.55 mm |
| June | 13.2 °C | 25.1 °C | 118.36 mm |
| July | 15.4 °C | 27.6 °C | 100.33 mm |
| August | 14.4 °C | 26.4 °C | 95.76 mm |
| September | 9.8 °C | 22.3 °C | 85.85 mm |
| October | 3.2 °C | 14.6 °C | 73.91 mm |
| November | -2.8 °C | 6.4 °C | 47.24 mm |
| December | -9.1 °C | -0.8 °C | 44.45 mm |
| Annual | 1.9 °C | 12.8 °C | 860.03 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |