Bay City, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 36.1 °F (low) to 55.5 °F (high). Annual precipitation averages 34.2 Inches. Bay City is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 1 - Oct. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 6.7 °F | 24.1 °F | 0.99 in. |
| February | 10.0 °F | 28.8 °F | 0.99 in. |
| March | 22.5 °F | 41.1 °F | 1.79 in. |
| April | 35.2 °F | 56.0 °F | 3.03 in. |
| May | 47.8 °F | 68.7 °F | 4.36 in. |
| June | 58.1 °F | 78.4 °F | 5.17 in. |
| July | 62.2 °F | 83.0 °F | 4.03 in. |
| August | 59.7 °F | 80.6 °F | 4.68 in. |
| September | 51.8 °F | 73.4 °F | 3.6 in. |
| October | 38.9 °F | 59.2 °F | 2.62 in. |
| November | 26.5 °F | 43.0 °F | 1.71 in. |
| December | 14.3 °F | 29.6 °F | 1.23 in. |
| Annual | 36.1 °F | 55.5 °F | 34.2 in. |
| Average First Frost Date | Oct. 1 - Oct. 10 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -20°F to -15°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 |