Milbank, South Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.6 °C (low) to 12.2 °C (high). Annual precipitation averages 632 Millimeters. Milbank 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 Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -16 °C | -5.6 °C | 15.49 mm |
| February | -14.2 °C | -3.2 °C | 15.49 mm |
| March | -7.1 °C | 3.6 °C | 29.21 mm |
| April | 0.1 °C | 12.4 °C | 64.26 mm |
| May | 7.4 °C | 19.9 °C | 73.41 mm |
| June | 13.7 °C | 25.5 °C | 99.82 mm |
| July | 15.8 °C | 27.9 °C | 99.06 mm |
| August | 14.3 °C | 26.8 °C | 76.71 mm |
| September | 9.2 °C | 22.6 °C | 58.42 mm |
| October | 1.8 °C | 14.3 °C | 58.17 mm |
| November | -5.3 °C | 5.3 °C | 23.11 mm |
| December | -12.2 °C | -2.6 °C | 18.8 mm |
| Annual | 0.6 °C | 12.2 °C | 631.95 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| 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 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |