Owatonna, Minnesota has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35.3 °F (low) to 54.5 °F (high). Annual precipitation averages 35.2 Inches. 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 | 5.8 °F | 22.6 °F | 0.87 in. |
| February | 9.6 °F | 27.2 °F | 1.01 in. |
| March | 22.1 °F | 39.7 °F | 1.92 in. |
| April | 34.4 °F | 55.2 °F | 3.14 in. |
| May | 47.0 °F | 67.9 °F | 4.46 in. |
| June | 57.9 °F | 78.0 °F | 5.24 in. |
| July | 61.2 °F | 81.3 °F | 4.73 in. |
| August | 58.7 °F | 79.2 °F | 4.69 in. |
| September | 50.3 °F | 72.8 °F | 3.78 in. |
| October | 37.4 °F | 58.9 °F | 2.47 in. |
| November | 25.4 °F | 42.4 °F | 1.63 in. |
| December | 13.2 °F | 28.5 °F | 1.23 in. |
| Annual | 35.3 °F | 54.5 °F | 35.17 in. |
| 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 : -25°F to -20°F |
| Plant Hardiness Zone - 2012 | Zone 4b : -25°F to -20°F |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |