Forbes, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.8 °F (low) to 53.4 °F (high). Annual precipitation averages 22.2 Inches. Forbes is located in USDA Plant Hardiness Zone 4b. 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 | 2.3 °F | 20.8 °F | 0.56 in. |
| February | 6.2 °F | 25.4 °F | 0.62 in. |
| March | 18.0 °F | 38.0 °F | 0.96 in. |
| April | 30.7 °F | 54.2 °F | 1.7 in. |
| May | 43.8 °F | 67.3 °F | 3.09 in. |
| June | 54.8 °F | 76.8 °F | 3.82 in. |
| July | 59.1 °F | 82.2 °F | 3.37 in. |
| August | 56.5 °F | 81.1 °F | 2.55 in. |
| September | 46.9 °F | 72.4 °F | 2.33 in. |
| October | 33.8 °F | 56.8 °F | 1.83 in. |
| November | 20.2 °F | 39.6 °F | 0.7 in. |
| December | 8.9 °F | 26.0 °F | 0.64 in. |
| Annual | 31.8 °F | 53.4 °F | 22.17 in. |
| 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 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |