Osseo, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 0.9 °C (low) to 12.6 °C (high). Annual precipitation averages 869.7 Millimeters. Osseo 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 | -15.1 °C | -4.6 °C | 27.43 mm |
| February | -13.2 °C | -1.8 °C | 26.42 mm |
| March | -6.5 °C | 5.1 °C | 44.45 mm |
| April | 0.4 °C | 13 °C | 81.79 mm |
| May | 7.2 °C | 20.2 °C | 106.93 mm |
| June | 12.9 °C | 25.3 °C | 130.3 mm |
| July | 15.1 °C | 27.6 °C | 99.82 mm |
| August | 13.8 °C | 26.4 °C | 107.44 mm |
| September | 9.2 °C | 22 °C | 96.77 mm |
| October | 2.4 °C | 14.3 °C | 69.34 mm |
| November | -4.1 °C | 5.7 °C | 43.69 mm |
| December | -10.9 °C | -1.7 °C | 35.31 mm |
| Annual | 0.9 °C | 12.6 °C | 869.69 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 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |