Marion, South Dakota has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 1.7 °C (low) to 13.7 °C (high). Annual precipitation averages 680.5 Millimeters. Marion 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 | -14 °C | -3.5 °C | 13.46 mm |
| February | -11.7 °C | -0.6 °C | 19.3 mm |
| March | -5.5 °C | 6.1 °C | 33.78 mm |
| April | 1.1 °C | 13.9 °C | 72.14 mm |
| May | 8.2 °C | 20.8 °C | 96.77 mm |
| June | 14.4 °C | 26.3 °C | 107.7 mm |
| July | 16.7 °C | 29 °C | 75.69 mm |
| August | 15.3 °C | 27.4 °C | 85.6 mm |
| September | 10.2 °C | 23.6 °C | 69.34 mm |
| October | 2.4 °C | 15.7 °C | 61.21 mm |
| November | -5.1 °C | 6.6 °C | 25.65 mm |
| December | -11.1 °C | -1.1 °C | 19.81 mm |
| Annual | 1.7 °C | 13.7 °C | 680.45 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |