Sibley, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 30 °F (low) to 50.5 °F (high). Annual precipitation averages 21.9 Inches. Sibley 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 | -1.6 °F | 16.0 °F | 0.53 in. |
| February | 2.2 °F | 21.1 °F | 0.51 in. |
| March | 15.3 °F | 33.5 °F | 0.85 in. |
| April | 29.5 °F | 51.2 °F | 1.15 in. |
| May | 42.5 °F | 65.9 °F | 2.87 in. |
| June | 54.2 °F | 75.1 °F | 3.79 in. |
| July | 58.0 °F | 80.0 °F | 3.61 in. |
| August | 55.0 °F | 79.1 °F | 2.86 in. |
| September | 46.0 °F | 70.4 °F | 2.43 in. |
| October | 33.3 °F | 54.7 °F | 1.8 in. |
| November | 18.9 °F | 36.8 °F | 0.73 in. |
| December | 6.3 °F | 22.1 °F | 0.72 in. |
| Annual | 30 °F | 50.5 °F | 21.85 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 |