Richardton, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 31.6 °F (low) to 54.3 °F (high). Annual precipitation averages 17.3 Inches. Richardton 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 | 5.9 °F | 24.7 °F | 0.34 in. |
| February | 9.3 °F | 28.6 °F | 0.41 in. |
| March | 19.3 °F | 40.6 °F | 0.55 in. |
| April | 30.1 °F | 54.2 °F | 1.26 in. |
| May | 41.5 °F | 65.6 °F | 2.65 in. |
| June | 51.6 °F | 75.1 °F | 3.39 in. |
| July | 57.0 °F | 82.9 °F | 2.5 in. |
| August | 55.5 °F | 82.7 °F | 1.82 in. |
| September | 45.9 °F | 72.7 °F | 1.83 in. |
| October | 33.0 °F | 56.2 °F | 1.52 in. |
| November | 20.2 °F | 39.9 °F | 0.57 in. |
| December | 10.3 °F | 28.5 °F | 0.41 in. |
| Annual | 31.6 °F | 54.3 °F | 17.25 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 4b : -25°F to -20°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |