Yankton, South Dakota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 2.8 °C (low) to 14.9 °C (high). Annual precipitation averages 693.9 Millimeters. Yankton is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -12.4 °C | -1.7 °C | 13.97 mm |
| February | -10.4 °C | 1.1 °C | 18.8 mm |
| March | -4.4 °C | 7.8 °C | 36.32 mm |
| April | 1.9 °C | 14.9 °C | 73.91 mm |
| May | 8.8 °C | 21.3 °C | 104.65 mm |
| June | 15 °C | 27.2 °C | 105.92 mm |
| July | 17.5 °C | 29.8 °C | 73.66 mm |
| August | 16.1 °C | 28.5 °C | 81.28 mm |
| September | 10.9 °C | 24.6 °C | 72.14 mm |
| October | 3.5 °C | 16.9 °C | 65.28 mm |
| November | -3.8 °C | 8.1 °C | 27.43 mm |
| December | -9.7 °C | 0.7 °C | 20.57 mm |
| Annual | 2.8 °C | 14.9 °C | 693.93 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Extreme Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |