Cathay, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.2 °C (low) to 10.5 °C (high). Annual precipitation averages 503.7 Millimeters. Cathay is located in USDA Plant Hardiness Zone 4a. 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 | -17.8 °C | -7.8 °C | 11.68 mm |
| February | -15.9 °C | -5.4 °C | 12.19 mm |
| March | -9.1 °C | 1.4 °C | 17.27 mm |
| April | -1.7 °C | 10.9 °C | 28.96 mm |
| May | 5.5 °C | 18.7 °C | 67.31 mm |
| June | 11.7 °C | 23.8 °C | 96.77 mm |
| July | 14.1 °C | 26.7 °C | 84.33 mm |
| August | 12.4 °C | 26.6 °C | 61.47 mm |
| September | 7.5 °C | 21.6 °C | 48.77 mm |
| October | 0.3 °C | 12.5 °C | 41.91 mm |
| November | -7.5 °C | 2.6 °C | 16.51 mm |
| December | -14.3 °C | -5.1 °C | 16.51 mm |
| Annual | -1.2 °C | 10.5 °C | 503.68 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 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |