May in Green Bay averages a daily high of 19.5°C with nights around 7.1°C. Expect roughly 10.7 wet days totalling 100.5mm. Comfortable conditions for being outdoors all day.
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 May data.