Bay City, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 2.3 °C (low) to 13.1 °C (high). Annual precipitation averages 868.7 Millimeters. 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 | -14.1 °C | -4.4 °C | 25.15 mm |
| February | -12.2 °C | -1.8 °C | 25.15 mm |
| March | -5.3 °C | 5.1 °C | 45.47 mm |
| April | 1.8 °C | 13.3 °C | 76.96 mm |
| May | 8.8 °C | 20.4 °C | 110.74 mm |
| June | 14.5 °C | 25.8 °C | 131.32 mm |
| July | 16.8 °C | 28.3 °C | 102.36 mm |
| August | 15.4 °C | 27 °C | 118.87 mm |
| September | 11 °C | 23 °C | 91.44 mm |
| October | 3.8 °C | 15.1 °C | 66.55 mm |
| November | -3.1 °C | 6.1 °C | 43.43 mm |
| December | -9.8 °C | -1.3 °C | 31.24 mm |
| Annual | 2.3 °C | 13.1 °C | 868.68 mm |
| 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 : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |