The highest day temperature in September 2025 was 84°F. The lowest night temperature was 47°F. The average values for day and night temperatures during September were 73.8°F и 60.5°F respectivly.

The average sea surface temperature in September 2025 for Milwaukee was 68.8°F. The maximum and minimum values were 65.0°F and 72.2°F respectively.

Most of the days in September are sunny but you can also expect cloudy and gloomy days.

Precipitation total in September for Milwaukee is 0.8 in.

The average wind speed in September is 9.4 mph.

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 Milwaukee in September is 8.1 hours.