The summer season in southeast Michigan bids a slow goodbye in September. According to NOAA National Data Centers, the average temperature in September is 63.9 degrees.
Temperatures: Typically, September Weather in Detroit is a big tease. It can stay summer warm or blast you with a preview of winter. The average temperature range is 54.1 to 73.7 degrees, but the occasional hot, humid day is still possible. Detroit has seen both highs of 98 degrees and lows of 29 degrees in September.
Rain? When it rains, it pours in September. While there are fewer days of rain (9), the average rainfall for the month is 3.27 inches.
Sunshine on a Cloudy Day? In September, sunshine is hit or miss. In fact, the possibility of sunshine is about 61%. Out of 30 days in the month, Detroit typically sees eight clear days, 10 partly-cloudy days and 12 cloudy days.