Tolley, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 28.4 °F (low) to 50.2 °F (high). Annual precipitation averages 17.8 Inches. Tolley 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 | -1.0 °F | 17.2 °F | 0.57 in. |
| February | 3.0 °F | 22.0 °F | 0.52 in. |
| March | 14.5 °F | 33.9 °F | 0.72 in. |
| April | 27.7 °F | 51.6 °F | 0.89 in. |
| May | 40.3 °F | 64.8 °F | 2.66 in. |
| June | 51.3 °F | 73.4 °F | 3.62 in. |
| July | 55.2 °F | 79.3 °F | 2.74 in. |
| August | 52.8 °F | 79.9 °F | 1.91 in. |
| September | 43.4 °F | 69.8 °F | 1.55 in. |
| October | 30.9 °F | 53.3 °F | 1.34 in. |
| November | 17.1 °F | 35.5 °F | 0.68 in. |
| December | 5.0 °F | 22.1 °F | 0.63 in. |
| Annual | 28.4 °F | 50.2 °F | 17.83 in. |
| 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 : -30°F to -25°F |
| Plant Hardiness Zone - 2012 | Zone 3b : -35°F to -30°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |