Blackduck, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -2 °C (low) to 9.9 °C (high). Annual precipitation averages 654.6 Millimeters. Blackduck is located in USDA Plant Hardiness Zone 3b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -19.7 °C | -8.2 °C | 16 mm |
| February | -18.3 °C | -4.8 °C | 15.49 mm |
| March | -10.6 °C | 2.6 °C | 24.89 mm |
| April | -2.5 °C | 10.4 °C | 43.43 mm |
| May | 4.9 °C | 17.9 °C | 74.42 mm |
| June | 10.8 °C | 22.9 °C | 107.19 mm |
| July | 13.3 °C | 25.5 °C | 101.35 mm |
| August | 11.8 °C | 24.8 °C | 81.53 mm |
| September | 7.3 °C | 19.7 °C | 77.22 mm |
| October | 0.8 °C | 11.4 °C | 62.23 mm |
| November | -6.7 °C | 2.1 °C | 30.23 mm |
| December | -14.7 °C | -5.2 °C | 20.57 mm |
| Annual | -2 °C | 9.9 °C | 654.55 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 3b : -37.2°C to -34.4°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |