Heimdal, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.5 °C (low) to 10.5 °C (high). Annual precipitation averages 498.1 Millimeters. Heimdal 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 | -18.2 °C | -8 °C | 10.41 mm |
| February | -16.4 °C | -5.7 °C | 10.92 mm |
| March | -9.3 °C | 1.2 °C | 17.02 mm |
| April | -1.9 °C | 11.1 °C | 28.7 mm |
| May | 5.4 °C | 18.9 °C | 68.83 mm |
| June | 11.6 °C | 23.7 °C | 96.52 mm |
| July | 13.9 °C | 26.8 °C | 83.57 mm |
| August | 12.4 °C | 26.7 °C | 59.44 mm |
| September | 7.4 °C | 21.7 °C | 52.83 mm |
| October | 0.1 °C | 12.6 °C | 36.83 mm |
| November | -7.8 °C | 2.5 °C | 17.02 mm |
| December | -14.7 °C | -5.3 °C | 16 mm |
| Annual | -1.5 °C | 10.5 °C | 498.09 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 |