Harwood, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.2 °C (low) to 11 °C (high). Annual precipitation averages 613.9 Millimeters. Harwood 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 Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -18.2 °C | -8.6 °C | 17.53 mm |
| February | -15.8 °C | -5.6 °C | 17.02 mm |
| March | -8.4 °C | 1.6 °C | 26.92 mm |
| April | -0.2 °C | 11.7 °C | 32.51 mm |
| May | 7.1 °C | 19.8 °C | 76.2 mm |
| June | 13.3 °C | 24.9 °C | 111.51 mm |
| July | 15.4 °C | 27.3 °C | 90.17 mm |
| August | 13.8 °C | 26.7 °C | 69.6 mm |
| September | 8.8 °C | 22 °C | 71.88 mm |
| October | 1.8 °C | 13.3 °C | 57.66 mm |
| November | -6.2 °C | 3.2 °C | 22.61 mm |
| December | -13.6 °C | -4.9 °C | 20.32 mm |
| Annual | -0.2 °C | 11 °C | 613.93 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |