Green Valley, South Dakota has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 2.2 °C (low) to 15.2 °C (high). Annual precipitation averages 457.7 Millimeters. Green Valley 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 | -9.9 °C | 2.3 °C | 8.38 mm |
| February | -8.9 °C | 3.3 °C | 12.45 mm |
| March | -4.3 °C | 8.8 °C | 24.38 mm |
| April | 0.6 °C | 13.3 °C | 52.07 mm |
| May | 6.6 °C | 18.6 °C | 95 mm |
| June | 12.2 °C | 25 °C | 76.2 mm |
| July | 15.8 °C | 29.8 °C | 55.12 mm |
| August | 14.7 °C | 29.3 °C | 42.67 mm |
| September | 9.6 °C | 24.2 °C | 32 mm |
| October | 2.4 °C | 16 °C | 37.59 mm |
| November | -3.9 °C | 8.8 °C | 12.45 mm |
| December | -8.7 °C | 3.1 °C | 9.4 mm |
| Annual | 2.2 °C | 15.2 °C | 457.71 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 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |