The highest day temperature in September 2026 was 94°F. The lowest night temperature was 50°F. The average values for day and night temperatures during September were 72.2°F и 60.1°F respectivly.

The average sea surface temperature in September 2026 for Green Bay was 72.1°F. The maximum and minimum values were 63.6°F and 79.8°F respectively.

You can expect various weather conditions during September. Be ready for sunny, cloudy or even gloomy days.

Precipitation total in September for Green Bay is 1.2 in. It makes september one of the most rainy months of the year.

The average wind speed in September is 8.8 mph. It makes September one of the most windless months of the year for Green Bay.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Green Bay in September is 7.3 hours.