Forman, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Annual precipitation averages 599.9 Millimeters. Forman is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -17.2 °C | -7.1 °C | 15.49 mm |
| February | -14.8 °C | -4.3 °C | 14.48 mm |
| March | -7.9 °C | 2.7 °C | 24.38 mm |
| April | -0.4 °C | 11.7 °C | 44.45 mm |
| May | 7.1 °C | 19.6 °C | 80.26 mm |
| June | 13.3 °C | 24.8 °C | 109.73 mm |
| July | 15.5 °C | 27.4 °C | 89.66 mm |
| August | 14 °C | 26.7 °C | 58.42 mm |
| September | 8.7 °C | 22.3 °C | 67.56 mm |
| October | 1.3 °C | 13.6 °C | 58.42 mm |
| November | -6.3 °C | 3.8 °C | 20.32 mm |
| December | -13 °C | -3.7 °C | 16.76 mm |
| Annual | 0 °C | 11.5 °C | 599.93 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |