Mound City, South Dakota has a Humid Continental Hot Summers With Dry Winters climate (Köppen classification: Dwa). Average annual temperatures range from 32.5 °F (low) to 55.1 °F (high). Annual precipitation averages 18.8 Inches. Mound City is located in USDA Plant Hardiness Zone 4b. 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 | 3.8 °F | 22.8 °F | 0.39 in. |
| February | 7.8 °F | 27.7 °F | 0.49 in. |
| March | 19.2 °F | 40.1 °F | 0.76 in. |
| April | 31.1 °F | 55.7 °F | 1.41 in. |
| May | 43.5 °F | 68.0 °F | 2.76 in. |
| June | 54.4 °F | 77.7 °F | 3.41 in. |
| July | 59.8 °F | 84.3 °F | 3.04 in. |
| August | 57.3 °F | 83.3 °F | 2.15 in. |
| September | 47.7 °F | 74.2 °F | 1.69 in. |
| October | 34.3 °F | 57.9 °F | 1.69 in. |
| November | 21.0 °F | 41.3 °F | 0.52 in. |
| December | 9.9 °F | 27.9 °F | 0.46 in. |
| Annual | 32.5 °F | 55.1 °F | 18.77 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 4b : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4a : -30°F to -25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dwa - Humid Continental Hot Summers With Dry Winters |