Norwalk, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.9 °F (low) to 55 °F (high). Annual precipitation averages 37.3 Inches. Norwalk 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 Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 7.5 °F | 24.9 °F | 1.18 in. |
| February | 10.6 °F | 29.6 °F | 1.11 in. |
| March | 22.0 °F | 41.7 °F | 1.85 in. |
| April | 33.8 °F | 55.9 °F | 3.8 in. |
| May | 45.7 °F | 67.9 °F | 4.77 in. |
| June | 55.8 °F | 77.1 °F | 5.36 in. |
| July | 59.6 °F | 81.0 °F | 4.41 in. |
| August | 57.3 °F | 79.0 °F | 4.56 in. |
| September | 48.9 °F | 71.6 °F | 3.9 in. |
| October | 37.3 °F | 58.4 °F | 2.87 in. |
| November | 25.9 °F | 43.1 °F | 1.97 in. |
| December | 14.8 °F | 30.3 °F | 1.52 in. |
| Annual | 34.9 °F | 55 °F | 37.3 in. |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| 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 | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |