Chicago, Illinois – A sharp blast of cooler air will sweep into the Midwest early next week, dropping temperatures well below normal across Illinois, Wisconsin, Iowa, and Michigan as September begins. Afternoon highs could struggle to reach the 60s in some areas, giving the region its first strong taste of fall.
According to the National Weather Service Climate Prediction Center, much of the Upper Midwest and Great Lakes is expected to run below average from Sunday through Thursday, with the strongest chill centered over Iowa, Illinois, and Michigan. The shift comes as a trough of cooler Canadian air dives south, replacing the recent stretch of summer warmth.
Cities including Chicago, Des Moines, Milwaukee, and Detroit may see daytime highs 10 to 15 degrees below early September averages. Overnight lows could dip into the upper 40s across northern Illinois and Wisconsin, raising concerns for chilly morning commutes and heavier use of furnaces earlier than normal.
Travelers should prepare for brisker conditions, especially during early morning hours. While no frost is expected this early in the season, cooler nights may impact late-summer crops and outdoor events.
The fall-like air mass is expected to dominate the region through midweek, with temperatures slowly rebounding late next week. Additional advisories could be issued if the cool stretch deepens or lingers longer than anticipated.
