Knox, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -2.4 °C (low) to 9.6 °C (high). Annual precipitation averages 494 Millimeters. Knox 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. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -19.8 °C | -9.3 °C | 12.19 mm |
| February | -17.8 °C | -6.8 °C | 12.7 mm |
| March | -10.7 °C | 0.1 °C | 19.3 mm |
| April | -2.4 °C | 10.1 °C | 24.38 mm |
| May | 4.8 °C | 18.2 °C | 69.09 mm |
| June | 11.1 °C | 23.1 °C | 93.73 mm |
| July | 13.3 °C | 26.1 °C | 83.06 mm |
| August | 11.7 °C | 25.8 °C | 59.69 mm |
| September | 6.5 °C | 20.8 °C | 46.23 mm |
| October | -0.7 °C | 11.7 °C | 37.34 mm |
| November | -8.8 °C | 1.4 °C | 20.07 mm |
| December | -16.1 °C | -6.5 °C | 16.26 mm |
| Annual | -2.4 °C | 9.6 °C | 494.04 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 3b : -37.2°C to -34.4°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |