Ferney, South Dakota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.3 °C (low) to 12.8 °C (high). Annual precipitation averages 584.7 Millimeters. Ferney is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -16.4 °C | -5.6 °C | 14.22 mm |
| February | -14.1 °C | -2.6 °C | 16 mm |
| March | -7.1 °C | 4.6 °C | 25.4 mm |
| April | -0.2 °C | 13.3 °C | 54.1 mm |
| May | 7.1 °C | 20.3 °C | 80.01 mm |
| June | 13.2 °C | 25.7 °C | 99.06 mm |
| July | 15.7 °C | 28.6 °C | 89.66 mm |
| August | 14.2 °C | 27.9 °C | 58.93 mm |
| September | 8.9 °C | 23.3 °C | 56.13 mm |
| October | 1.3 °C | 14.9 °C | 55.12 mm |
| November | -6.3 °C | 5.3 °C | 19.56 mm |
| December | -12.9 °C | -2.5 °C | 16.51 mm |
| Annual | 0.3 °C | 12.8 °C | 584.7 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |