Hamilton, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 28.6 °F (low) to 48.5 °F (high). Annual precipitation averages 21.9 Inches. Hamilton 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.9 °F | 13.1 °F | 0.6 in. |
| February | -0.9 °F | 17.8 °F | 0.54 in. |
| March | 13.3 °F | 30.8 °F | 0.84 in. |
| April | 29.0 °F | 49.7 °F | 1.08 in. |
| May | 41.7 °F | 64.4 °F | 3.17 in. |
| June | 53.2 °F | 74.2 °F | 3.89 in. |
| July | 57.0 °F | 78.7 °F | 3.23 in. |
| August | 53.9 °F | 78.2 °F | 2.78 in. |
| September | 45.3 °F | 69.0 °F | 2.26 in. |
| October | 32.9 °F | 52.7 °F | 1.71 in. |
| November | 18.1 °F | 34.1 °F | 0.96 in. |
| December | 3.7 °F | 19.3 °F | 0.83 in. |
| Annual | 28.6 °F | 48.5 °F | 21.89 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 3b : -35°F to -30°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |