Tolna, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.3 °C (low) to 9.5 °C (high). Annual precipitation averages 528.6 Millimeters. Tolna 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 | -18.9 °C | -9.4 °C | 12.45 mm |
| February | -16.9 °C | -6.8 °C | 11.43 mm |
| March | -9.6 °C | 0.1 °C | 19.56 mm |
| April | -1.7 °C | 9.7 °C | 25.15 mm |
| May | 5.8 °C | 18.3 °C | 68.58 mm |
| June | 12.2 °C | 23.2 °C | 100.08 mm |
| July | 14.6 °C | 25.8 °C | 94.74 mm |
| August | 13.1 °C | 25.7 °C | 66.55 mm |
| September | 7.8 °C | 20.8 °C | 52.32 mm |
| October | 0.5 °C | 11.7 °C | 40.89 mm |
| November | -7.6 °C | 1.6 °C | 19.81 mm |
| December | -14.7 °C | -6.3 °C | 17.02 mm |
| Annual | -1.3 °C | 9.5 °C | 528.58 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 |