Sibley, 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 10.3 °C (high). Annual precipitation averages 555 Millimeters. 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 | -18.7 °C | -8.9 °C | 13.46 mm |
| February | -16.6 °C | -6.1 °C | 12.95 mm |
| March | -9.3 °C | 0.8 °C | 21.59 mm |
| April | -1.4 °C | 10.7 °C | 29.21 mm |
| May | 5.8 °C | 18.8 °C | 72.9 mm |
| June | 12.3 °C | 23.9 °C | 96.27 mm |
| July | 14.4 °C | 26.7 °C | 91.69 mm |
| August | 12.8 °C | 26.2 °C | 72.64 mm |
| September | 7.8 °C | 21.3 °C | 61.72 mm |
| October | 0.7 °C | 12.6 °C | 45.72 mm |
| November | -7.3 °C | 2.7 °C | 18.54 mm |
| December | -14.3 °C | -5.5 °C | 18.29 mm |
| Annual | -1.2 °C | 10.3 °C | 554.98 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |