Sisseton, 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 11.9 °C (high). Annual precipitation averages 645.9 Millimeters. Sisseton 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 | -16.2 °C | -6.3 °C | 17.27 mm |
| February | -14.2 °C | -3.8 °C | 21.34 mm |
| March | -7.4 °C | 3.2 °C | 30.99 mm |
| April | 0.1 °C | 12.1 °C | 63.25 mm |
| May | 7.4 °C | 19.7 °C | 74.68 mm |
| June | 13.6 °C | 25.1 °C | 102.62 mm |
| July | 15.9 °C | 27.6 °C | 95 mm |
| August | 14.4 °C | 26.7 °C | 62.48 mm |
| September | 9.4 °C | 22.4 °C | 63.75 mm |
| October | 2.1 °C | 13.9 °C | 64.26 mm |
| November | -5.3 °C | 4.7 °C | 27.43 mm |
| December | -12.3 °C | -2.9 °C | 22.86 mm |
| Annual | 0.6 °C | 11.9 °C | 645.93 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 |