WISCONSIN — Fall is just around the corner, and that means cooler weather isn't far off. So how long before our first freeze? Well, it's hard to say exactly at this point, but we can look back at climate data to get an idea.
The median dates for the first freeze in Southeast Wisconsin range from October 1st to October 20th. That date range is October 11th to the 20th for areas a little closer to Lake Michigan. The warmth of the lake helps to keep those areas warmer a little longer than inland locations.
Now, let's look at extremes - the earliest cases of cold weather hitting Southeast Wisconsin. It's not out of question to see temperatures dropping into the 30s in September!
The earliest [fall] date on record with a temperature below freezing in Milwaukee was September 20, 1956, when the low dropped to 30°. The earliest trace of [fall] snow on record for Milwaukee was recorded on September 23, 1942.
On the other hand, early fall can be quite warm. There are many days in October with record high temperatures in the 80s.
The Climate Prediction Center temperature outlook for September, October, and November shows a slight probability for above average temperatures across Wisconsin.
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