Interior, South Dakota has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from 2.1 °C (low) to 16.9 °C (high). Annual precipitation averages 490.5 Millimeters. Interior is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.8 °C | 1.9 °C | 10.92 mm |
| February | -9.4 °C | 3.9 °C | 13.97 mm |
| March | -4.5 °C | 10 °C | 28.45 mm |
| April | 0.8 °C | 16.1 °C | 57.91 mm |
| May | 7.2 °C | 21.7 °C | 87.88 mm |
| June | 12.9 °C | 27.5 °C | 87.12 mm |
| July | 16.6 °C | 32.2 °C | 59.69 mm |
| August | 15.2 °C | 32.1 °C | 43.94 mm |
| September | 9.6 °C | 27.1 °C | 33.53 mm |
| October | 2.3 °C | 18.3 °C | 40.64 mm |
| November | -4.8 °C | 9.3 °C | 13.97 mm |
| December | -9.7 °C | 2.9 °C | 12.45 mm |
| Annual | 2.1 °C | 16.9 °C | 490.47 mm |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 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 | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |