December in Green Bay averages a daily high of 0.1°C with nights around -8°C. Expect roughly 8.1 wet days totalling 52.1mm. A hard month to visit for comfort alone.
Across the year, the best time to visit Green Bay is May–September.
Based on GREEN BAY BOTANICAL, WI US (6.4km), 1995–2024. 19 years of December data.