The highest day temperature in September 2025 was 91°F. The lowest night temperature was 45°F. The average values for day and night temperatures during September were 78.7°F и 58.3°F respectivly.

The average sea surface temperature in September 2025 for South Haven was 70.5°F. The maximum and minimum values were 68.0°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 South Haven is 0.6 in. It makes september one of the least rainy months of the year.

The average wind speed in September is 9.6 mph. It makes September one of the most windless months of the year for South Haven.

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 South Haven in September is 8.3 hours.