Perth, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 27.1 °F (low) to 47.9 °F (high). Annual precipitation averages 20.4 Inches. Perth is located in USDA Plant Hardiness Zone 3b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.8 °F | 14.6 °F | 0.62 in. |
| February | -0.6 °F | 18.9 °F | 0.63 in. |
| March | 12.4 °F | 30.8 °F | 0.87 in. |
| April | 27.0 °F | 48.8 °F | 0.96 in. |
| May | 39.8 °F | 63.2 °F | 2.77 in. |
| June | 51.1 °F | 72.2 °F | 3.74 in. |
| July | 55.1 °F | 77.1 °F | 3.25 in. |
| August | 52.5 °F | 77.1 °F | 2.62 in. |
| September | 43.2 °F | 67.7 °F | 1.89 in. |
| October | 30.4 °F | 51.4 °F | 1.46 in. |
| November | 15.8 °F | 33.2 °F | 0.79 in. |
| December | 2.6 °F | 19.4 °F | 0.76 in. |
| Annual | 27.1 °F | 47.9 °F | 20.36 in. |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 3b : -35°F to -30°F |
| Plant Hardiness Zone - 2012 | Zone 3b : -35°F to -30°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |