Green Bay, Wisconsin has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from 35 °F (low) to 54 °F (high). Annual precipitation averages 32.6 Inches. Green 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 | 9.9 °F | 25.5 °F | 1.55 in. |
| February | 11.1 °F | 28.7 °F | 1.2 in. |
| March | 21.1 °F | 39.3 °F | 1.84 in. |
| April | 32.4 °F | 52.6 °F | 3.24 in. |
| May | 43.8 °F | 65.6 °F | 3.76 in. |
| June | 53.8 °F | 75.1 °F | 4.08 in. |
| July | 58.6 °F | 79.8 °F | 3.67 in. |
| August | 57.4 °F | 78.1 °F | 3.42 in. |
| September | 49.2 °F | 71.0 °F | 3.34 in. |
| October | 38.2 °F | 57.6 °F | 2.81 in. |
| November | 27.5 °F | 43.4 °F | 1.94 in. |
| December | 16.8 °F | 31.2 °F | 1.77 in. |
| Annual | 35 °F | 54 °F | 32.62 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 |