Fortuna, North Dakota has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -2.4 °C (low) to 10.2 °C (high). Annual precipitation averages 387.6 Millimeters. Fortuna is located in USDA Plant Hardiness Zone 3b. The growing season typically runs from the last frost around May 11 - May 20 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -18.2 °C | -7.6 °C | 13.72 mm |
| February | -16 °C | -5.1 °C | 10.92 mm |
| March | -9.4 °C | 1.6 °C | 15.49 mm |
| April | -2.4 °C | 11 °C | 25.15 mm |
| May | 4.1 °C | 18.1 °C | 48.77 mm |
| June | 9.8 °C | 22.6 °C | 89.15 mm |
| July | 12.4 °C | 26.5 °C | 63.25 mm |
| August | 11.2 °C | 26.6 °C | 39.62 mm |
| September | 5.6 °C | 20.7 °C | 35.05 mm |
| October | -1.4 °C | 11.7 °C | 23.37 mm |
| November | -8.8 °C | 1.7 °C | 11.18 mm |
| December | -15.1 °C | -5.1 °C | 11.94 mm |
| Annual | -2.4 °C | 10.2 °C | 387.61 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 3b : -37.2°C to -34.4°C |
| Plant Hardiness Zone - 2012 | Zone 3b : -37.2°C to -34.4°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |