Hillman, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.4 °C (low) to 10.9 °C (high). Annual precipitation averages 763.5 Millimeters. Hillman is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -18 °C | -6.9 °C | 18.03 mm |
| February | -16.1 °C | -3.9 °C | 20.32 mm |
| March | -8.7 °C | 3.2 °C | 36.32 mm |
| April | -1.2 °C | 11.2 °C | 64.26 mm |
| May | 6.4 °C | 18.8 °C | 92.2 mm |
| June | 12.2 °C | 23.9 °C | 115.82 mm |
| July | 14.8 °C | 26.5 °C | 108.97 mm |
| August | 13.4 °C | 25.3 °C | 98.81 mm |
| September | 8.9 °C | 20.8 °C | 74.42 mm |
| October | 1.8 °C | 12.7 °C | 73.41 mm |
| November | -5.6 °C | 3.5 °C | 35.81 mm |
| December | -13.2 °C | -3.9 °C | 25.15 mm |
| Annual | -0.4 °C | 10.9 °C | 763.52 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |