Owatonna, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 1.8 °C (low) to 12.5 °C (high). Annual precipitation averages 893.3 Millimeters. Owatonna 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 | -14.6 °C | -5.2 °C | 22.1 mm |
| February | -12.4 °C | -2.7 °C | 25.65 mm |
| March | -5.5 °C | 4.3 °C | 48.77 mm |
| April | 1.3 °C | 12.9 °C | 79.76 mm |
| May | 8.3 °C | 19.9 °C | 113.28 mm |
| June | 14.4 °C | 25.6 °C | 133.1 mm |
| July | 16.2 °C | 27.4 °C | 120.14 mm |
| August | 14.8 °C | 26.2 °C | 119.13 mm |
| September | 10.2 °C | 22.7 °C | 96.01 mm |
| October | 3 °C | 14.9 °C | 62.74 mm |
| November | -3.7 °C | 5.8 °C | 41.4 mm |
| December | -10.4 °C | -1.9 °C | 31.24 mm |
| Annual | 1.8 °C | 12.5 °C | 893.32 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 | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |