Gilby, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 29.9 °F (low) to 50.3 °F (high). Annual precipitation averages 21.5 Inches. 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 | -2.2 °F | 15.0 °F | 0.54 in. |
| February | 1.4 °F | 20.1 °F | 0.53 in. |
| March | 15.1 °F | 32.8 °F | 0.82 in. |
| April | 30.1 °F | 51.4 °F | 1.01 in. |
| May | 42.8 °F | 66.3 °F | 3.04 in. |
| June | 54.4 °F | 75.7 °F | 3.88 in. |
| July | 57.9 °F | 80.2 °F | 3.11 in. |
| August | 55.1 °F | 79.7 °F | 2.89 in. |
| September | 46.0 °F | 70.6 °F | 2.3 in. |
| October | 33.7 °F | 54.4 °F | 1.78 in. |
| November | 19.1 °F | 35.8 °F | 0.83 in. |
| December | 5.7 °F | 21.3 °F | 0.72 in. |
| Annual | 29.9 °F | 50.3 °F | 21.45 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 4a : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |