Winchester, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.3 °F (low) to 55 °F (high). Annual precipitation averages 33.5 Inches. Winchester is located in USDA Plant Hardiness Zone 5b. 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 | 10.0 °F | 25.5 °F | 1.37 in. |
| February | 12.1 °F | 29.2 °F | 1.19 in. |
| March | 22.4 °F | 40.7 °F | 1.89 in. |
| April | 34.3 °F | 54.4 °F | 3.3 in. |
| May | 46.3 °F | 67.1 °F | 3.88 in. |
| June | 56.6 °F | 76.7 °F | 4.68 in. |
| July | 60.7 °F | 81.4 °F | 3.82 in. |
| August | 58.9 °F | 79.2 °F | 3.64 in. |
| September | 50.7 °F | 72.1 °F | 3.24 in. |
| October | 38.9 °F | 58.3 °F | 2.85 in. |
| November | 27.9 °F | 43.8 °F | 1.91 in. |
| December | 16.7 °F | 31.1 °F | 1.7 in. |
| Annual | 36.3 °F | 55 °F | 33.47 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 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 |