Tolley, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -2 °C (low) to 10.1 °C (high). Annual precipitation averages 452.9 Millimeters. 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 | -18.3 °C | -8.2 °C | 14.48 mm |
| February | -16.1 °C | -5.6 °C | 13.21 mm |
| March | -9.7 °C | 1.1 °C | 18.29 mm |
| April | -2.4 °C | 10.9 °C | 22.61 mm |
| May | 4.6 °C | 18.2 °C | 67.56 mm |
| June | 10.7 °C | 23 °C | 91.95 mm |
| July | 12.9 °C | 26.3 °C | 69.6 mm |
| August | 11.6 °C | 26.6 °C | 48.51 mm |
| September | 6.3 °C | 21 °C | 39.37 mm |
| October | -0.6 °C | 11.8 °C | 34.04 mm |
| November | -8.3 °C | 1.9 °C | 17.27 mm |
| December | -15 °C | -5.5 °C | 16 mm |
| Annual | -2 °C | 10.1 °C | 452.89 mm |
| 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 : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |