Gilby, 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 10.2 °C (high). Annual precipitation averages 544.8 Millimeters. Gilby is located in USDA Plant Hardiness Zone 4a. 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 | -19 °C | -9.4 °C | 13.72 mm |
| February | -17 °C | -6.6 °C | 13.46 mm |
| March | -9.4 °C | 0.4 °C | 20.83 mm |
| April | -1.1 °C | 10.8 °C | 25.65 mm |
| May | 6 °C | 19.1 °C | 77.22 mm |
| June | 12.4 °C | 24.3 °C | 98.55 mm |
| July | 14.4 °C | 26.8 °C | 78.99 mm |
| August | 12.8 °C | 26.5 °C | 73.41 mm |
| September | 7.8 °C | 21.4 °C | 58.42 mm |
| October | 0.9 °C | 12.4 °C | 45.21 mm |
| November | -7.2 °C | 2.1 °C | 21.08 mm |
| December | -14.6 °C | -5.9 °C | 18.29 mm |
| Annual | -1.2 °C | 10.2 °C | 544.83 mm |
| 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 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |