Hillman, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.2 °F (low) to 51.7 °F (high). Annual precipitation averages 30.1 Inches. 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 | -0.4 °F | 19.5 °F | 0.71 in. |
| February | 3.0 °F | 25.0 °F | 0.8 in. |
| March | 16.3 °F | 37.8 °F | 1.43 in. |
| April | 29.9 °F | 52.1 °F | 2.53 in. |
| May | 43.5 °F | 65.8 °F | 3.63 in. |
| June | 54.0 °F | 75.1 °F | 4.56 in. |
| July | 58.6 °F | 79.7 °F | 4.29 in. |
| August | 56.2 °F | 77.6 °F | 3.89 in. |
| September | 48.0 °F | 69.5 °F | 2.93 in. |
| October | 35.3 °F | 54.8 °F | 2.89 in. |
| November | 21.9 °F | 38.3 °F | 1.41 in. |
| December | 8.3 °F | 24.9 °F | 0.99 in. |
| Annual | 31.2 °F | 51.7 °F | 30.06 in. |
| 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 : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |