Harvey, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.6 °C (low) to 10.5 °C (high). Annual precipitation averages 461.3 Millimeters. Harvey 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 | -18.2 °C | -7.9 °C | 8.89 mm |
| February | -16.6 °C | -5.8 °C | 9.14 mm |
| March | -9.4 °C | 1.3 °C | 15.75 mm |
| April | -1.9 °C | 11 °C | 26.67 mm |
| May | 5.3 °C | 18.7 °C | 66.8 mm |
| June | 11.4 °C | 23.4 °C | 89.66 mm |
| July | 13.8 °C | 26.7 °C | 76.2 mm |
| August | 12.1 °C | 26.6 °C | 55.88 mm |
| September | 7.1 °C | 21.5 °C | 48.26 mm |
| October | 0 °C | 12.7 °C | 36.83 mm |
| November | -7.9 °C | 2.6 °C | 14.48 mm |
| December | -14.9 °C | -5.3 °C | 12.7 mm |
| Annual | -1.6 °C | 10.5 °C | 461.26 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |