Mound City, South Dakota has a Humid Continental Hot Summers With Dry Winters climate (Köppen classification: Dwa). Average annual temperatures range from 0.3 °C (low) to 12.8 °C (high). Annual precipitation averages 476.8 Millimeters. 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 | -15.7 °C | -5.1 °C | 9.91 mm |
| February | -13.4 °C | -2.4 °C | 12.45 mm |
| March | -7.1 °C | 4.5 °C | 19.3 mm |
| April | -0.5 °C | 13.2 °C | 35.81 mm |
| May | 6.4 °C | 20 °C | 70.1 mm |
| June | 12.4 °C | 25.4 °C | 86.61 mm |
| July | 15.4 °C | 29.1 °C | 77.22 mm |
| August | 14.1 °C | 28.5 °C | 54.61 mm |
| September | 8.7 °C | 23.4 °C | 42.93 mm |
| October | 1.3 °C | 14.4 °C | 42.93 mm |
| November | -6.1 °C | 5.2 °C | 13.21 mm |
| December | -12.3 °C | -2.3 °C | 11.68 mm |
| Annual | 0.3 °C | 12.8 °C | 476.76 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 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dwa - Humid Continental Hot Summers With Dry Winters |