Williams Bay, Wisconsin has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 37.9 °F (low) to 57.5 °F (high). Annual precipitation averages 38.1 Inches. Williams Bay 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 | 13.2 °F | 28.7 °F | 1.82 in. |
| February | 15.9 °F | 32.7 °F | 1.79 in. |
| March | 25.3 °F | 44.3 °F | 2.2 in. |
| April | 35.6 °F | 57.4 °F | 3.77 in. |
| May | 47.3 °F | 69.0 °F | 4.34 in. |
| June | 56.8 °F | 78.7 °F | 5.51 in. |
| July | 61.2 °F | 82.5 °F | 3.64 in. |
| August | 59.4 °F | 81.0 °F | 4.07 in. |
| September | 51.5 °F | 74.4 °F | 3.61 in. |
| October | 40.2 °F | 61.2 °F | 2.97 in. |
| November | 29.5 °F | 46.4 °F | 2.37 in. |
| December | 19.1 °F | 33.9 °F | 2.04 in. |
| Annual | 37.9 °F | 57.5 °F | 38.13 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -15°F to -10°F |
| Plant Hardiness Zone - 2012 | Zone 5b : -15°F to -10°F |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |