Tolna, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 29.7 °F (low) to 49.2 °F (high). Annual precipitation averages 20.8 Inches. 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 | -2.0 °F | 15.0 °F | 0.49 in. |
| February | 1.5 °F | 19.8 °F | 0.45 in. |
| March | 14.8 °F | 32.2 °F | 0.77 in. |
| April | 28.9 °F | 49.5 °F | 0.99 in. |
| May | 42.5 °F | 65.0 °F | 2.7 in. |
| June | 53.9 °F | 73.7 °F | 3.94 in. |
| July | 58.2 °F | 78.5 °F | 3.73 in. |
| August | 55.6 °F | 78.3 °F | 2.62 in. |
| September | 46.1 °F | 69.4 °F | 2.06 in. |
| October | 32.9 °F | 53.1 °F | 1.61 in. |
| November | 18.4 °F | 34.8 °F | 0.78 in. |
| December | 5.6 °F | 20.7 °F | 0.67 in. |
| Annual | 29.7 °F | 49.2 °F | 20.81 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 |