Omro, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 37 °F (low) to 55.2 °F (high). Annual precipitation averages 33.5 Inches. Omro is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 10.5 °F | 25.9 °F | 1.54 in. |
| February | 12.7 °F | 29.5 °F | 1.34 in. |
| March | 23.1 °F | 41.0 °F | 1.96 in. |
| April | 35.0 °F | 54.5 °F | 3.36 in. |
| May | 47.1 °F | 67.0 °F | 3.98 in. |
| June | 57.3 °F | 76.9 °F | 4.68 in. |
| July | 61.5 °F | 81.5 °F | 3.68 in. |
| August | 59.7 °F | 79.4 °F | 3.41 in. |
| September | 51.7 °F | 72.4 °F | 3.08 in. |
| October | 39.8 °F | 58.6 °F | 2.77 in. |
| November | 28.5 °F | 44.2 °F | 1.93 in. |
| December | 17.3 °F | 31.5 °F | 1.76 in. |
| Annual | 37 °F | 55.2 °F | 33.49 in. |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5a : -20°F to -15°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |