Millston, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 33.3 °F (low) to 55.6 °F (high). Annual precipitation averages 36.2 Inches. Millston 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 | 5.4 °F | 25.2 °F | 1.18 in. |
| February | 8.3 °F | 30.2 °F | 1.11 in. |
| March | 20.1 °F | 42.2 °F | 1.83 in. |
| April | 32.2 °F | 56.2 °F | 3.58 in. |
| May | 44.4 °F | 68.6 °F | 4.51 in. |
| June | 54.2 °F | 77.8 °F | 5.36 in. |
| July | 58.1 °F | 81.7 °F | 4.22 in. |
| August | 55.9 °F | 79.6 °F | 4.42 in. |
| September | 47.4 °F | 72.3 °F | 3.77 in. |
| October | 35.7 °F | 59.0 °F | 2.9 in. |
| November | 24.4 °F | 43.4 °F | 1.83 in. |
| December | 13.0 °F | 30.4 °F | 1.5 in. |
| Annual | 33.3 °F | 55.6 °F | 36.21 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 | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |