Wallace, South Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.4 °C (low) to 11.7 °C (high). Annual precipitation averages 617 Millimeters. Wallace 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 | -6.1 °C | 16.51 mm |
| February | -14.2 °C | -3.4 °C | 16.76 mm |
| March | -7.5 °C | 3.4 °C | 26.92 mm |
| April | -0.3 °C | 11.9 °C | 57.66 mm |
| May | 6.9 °C | 19.2 °C | 78.74 mm |
| June | 13.1 °C | 24.6 °C | 100.33 mm |
| July | 15.7 °C | 27.4 °C | 92.2 mm |
| August | 14.3 °C | 26.5 °C | 67.82 mm |
| September | 9.4 °C | 22.1 °C | 63.75 mm |
| October | 1.7 °C | 13.7 °C | 57.66 mm |
| November | -5.8 °C | 4.5 °C | 20.32 mm |
| December | -12.4 °C | -3.1 °C | 18.29 mm |
| Annual | 0.4 °C | 11.7 °C | 616.96 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |