New Underwood, South Dakota has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 1.5 °C (low) to 15.6 °C (high). Annual precipitation averages 436.6 Millimeters. New Underwood is located in USDA Plant Hardiness Zone 5a. 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 | -10.9 °C | 1.8 °C | 8.13 mm |
| February | -9.7 °C | 3.3 °C | 10.41 mm |
| March | -4.8 °C | 9 °C | 22.1 mm |
| April | 0.1 °C | 14 °C | 47.5 mm |
| May | 6.2 °C | 19.6 °C | 88.39 mm |
| June | 11.8 °C | 25.7 °C | 76.96 mm |
| July | 15.4 °C | 30.4 °C | 54.1 mm |
| August | 14.3 °C | 30.2 °C | 41.66 mm |
| September | 8.8 °C | 25 °C | 30.99 mm |
| October | 1.6 °C | 16.4 °C | 37.59 mm |
| November | -4.9 °C | 8.8 °C | 10.67 mm |
| December | -9.8 °C | 2.7 °C | 8.13 mm |
| Annual | 1.5 °C | 15.6 °C | 436.63 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 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |