Frankfort, South Dakota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 0.5 °C (low) to 13.1 °C (high). Annual precipitation averages 582.7 Millimeters. Frankfort 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 °C | -5.1 °C | 12.7 mm |
| February | -13.6 °C | -2.1 °C | 16.51 mm |
| March | -6.8 °C | 5.1 °C | 24.13 mm |
| April | -0.1 °C | 13.4 °C | 55.63 mm |
| May | 7.2 °C | 20.4 °C | 81.03 mm |
| June | 13.3 °C | 25.9 °C | 97.79 mm |
| July | 15.9 °C | 29 °C | 85.6 mm |
| August | 14.3 °C | 28.1 °C | 63.75 mm |
| September | 8.9 °C | 23.6 °C | 58.67 mm |
| October | 1.4 °C | 15.1 °C | 53.34 mm |
| November | -6.2 °C | 5.8 °C | 18.29 mm |
| December | -12.7 °C | -2.1 °C | 15.24 mm |
| Annual | 0.5 °C | 13.1 °C | 582.68 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 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |