Milltown, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 34.1 °F (low) to 53.4 °F (high). Annual precipitation averages 32.5 Inches. Milltown 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 | 4.7 °F | 21.5 °F | 0.84 in. |
| February | 7.8 °F | 26.8 °F | 0.85 in. |
| March | 20.3 °F | 39.6 °F | 1.49 in. |
| April | 33.0 °F | 54.3 °F | 2.8 in. |
| May | 45.6 °F | 67.7 °F | 4.02 in. |
| June | 55.5 °F | 76.7 °F | 4.33 in. |
| July | 59.8 °F | 80.9 °F | 4.3 in. |
| August | 57.8 °F | 78.9 °F | 4.19 in. |
| September | 50.1 °F | 71.0 °F | 3.5 in. |
| October | 38.0 °F | 56.8 °F | 3.21 in. |
| November | 24.9 °F | 39.9 °F | 1.79 in. |
| December | 12.1 °F | 26.6 °F | 1.18 in. |
| Annual | 34.1 °F | 53.4 °F | 32.5 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 4a : -30°F to -25°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |