Marion, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.3 °C (low) to 12.5 °C (high). Annual precipitation averages 841.3 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 | -13.4 °C | -3.9 °C | 31.75 mm |
| February | -12.6 °C | -1.8 °C | 27.94 mm |
| March | -6.5 °C | 4.7 °C | 45.47 mm |
| April | 0.3 °C | 12.4 °C | 78.23 mm |
| May | 7.1 °C | 19.6 °C | 96.77 mm |
| June | 12.6 °C | 24.8 °C | 114.05 mm |
| July | 14.9 °C | 27.2 °C | 98.55 mm |
| August | 13.8 °C | 26.1 °C | 93.98 mm |
| September | 9.2 °C | 21.8 °C | 91.19 mm |
| October | 2.7 °C | 14.3 °C | 74.42 mm |
| November | -3.3 °C | 6.2 °C | 48.01 mm |
| December | -9.6 °C | -1.1 °C | 40.89 mm |
| Annual | 1.3 °C | 12.5 °C | 841.25 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |