Hillsboro, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 30.7 °F (low) to 51 °F (high). Annual precipitation averages 23.2 Inches. Hillsboro is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -1.7 °F | 15.9 °F | 0.62 in. |
| February | 2.2 °F | 21.1 °F | 0.6 in. |
| March | 15.9 °F | 33.8 °F | 0.95 in. |
| April | 30.9 °F | 52.1 °F | 1.27 in. |
| May | 43.6 °F | 66.7 °F | 2.9 in. |
| June | 55.3 °F | 76.3 °F | 4.08 in. |
| July | 58.7 °F | 80.7 °F | 3.66 in. |
| August | 55.5 °F | 79.7 °F | 2.68 in. |
| September | 46.7 °F | 71.0 °F | 2.77 in. |
| October | 34.5 °F | 55.1 °F | 2.03 in. |
| November | 20.0 °F | 37.3 °F | 0.82 in. |
| December | 6.5 °F | 22.0 °F | 0.77 in. |
| Annual | 30.7 °F | 51 °F | 23.15 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 11 - May 20 |
| 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 |