Hampden, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -2.3 °C (low) to 8.9 °C (high). Annual precipitation averages 515.9 Millimeters. Hampden 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 | -20.1 °C | -10.3 °C | 12.7 mm |
| February | -18.5 °C | -7.7 °C | 11.43 mm |
| March | -10.9 °C | -0.8 °C | 18.03 mm |
| April | -2.3 °C | 9.3 °C | 24.38 mm |
| May | 4.9 °C | 17.6 °C | 73.91 mm |
| June | 11.3 °C | 22.8 °C | 98.81 mm |
| July | 13.6 °C | 25.4 °C | 86.87 mm |
| August | 12.2 °C | 25.3 °C | 64.52 mm |
| September | 6.8 °C | 20.1 °C | 50.55 mm |
| October | -0.4 °C | 11.1 °C | 37.85 mm |
| November | -8.6 °C | 0.8 °C | 19.81 mm |
| December | -16.1 °C | -7.3 °C | 17.02 mm |
| Annual | -2.3 °C | 8.9 °C | 515.88 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |