South Heart, North Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 30.3 °F (low) to 54.7 °F (high). Annual precipitation averages 16.6 Inches. South Heart 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 | 4.9 °F | 25.4 °F | 0.35 in. |
| February | 8.4 °F | 29.8 °F | 0.43 in. |
| March | 18.2 °F | 41.1 °F | 0.71 in. |
| April | 28.8 °F | 54.1 °F | 1.15 in. |
| May | 40.3 °F | 65.5 °F | 2.53 in. |
| June | 50.4 °F | 74.9 °F | 3.14 in. |
| July | 55.7 °F | 83.0 °F | 2.55 in. |
| August | 53.6 °F | 83.1 °F | 1.6 in. |
| September | 44.0 °F | 72.8 °F | 1.82 in. |
| October | 31.3 °F | 56.5 °F | 1.35 in. |
| November | 19.0 °F | 40.7 °F | 0.53 in. |
| December | 9.1 °F | 29.4 °F | 0.41 in. |
| Annual | 30.3 °F | 54.7 °F | 16.57 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 11 - May 20 |
| Average Days With Frost | Over 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 | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |