Weather
Chicago Fall Begins Lows in 40s, Lake Michigan Risk
Chicago, Illinois – Fall begins Tuesday with highs of 61 to 66 degrees, a few possible showers and a high swim risk at Lake Michigan beaches.
By Elliot Vaughn · 2026-09-22T09:20:41.907Z
Chicago, Illinois – Fall begins Tuesday with highs of 61 to 66 degrees, a few possible showers and a high swim risk at Lake Michigan beaches.
According to the National Weather Service in Chicago, astronomical fall begins at 7:05 p.m. CDT Tuesday. Seasonably cool temperatures will continue through the week, with many locations remaining dry despite the possibility of a few showers Tuesday into Tuesday night.
Tuesday night temperatures will fall to between 49 and 58 degrees. The mildest readings are expected in and near Chicago and along the Lake Michigan shoreline.
Beach conditions present a more immediate safety concern. The Weather Service indicates a high swim risk at Lake Michigan beaches Tuesday. Beachgoers should check current conditions and avoid entering the water where dangerous waves or currents are present.
Temperatures begin a modest rebound Wednesday, when highs range from 65 to 68 degrees. Overnight lows will again fall to between 49 and 58.
Thursday through Saturday brings remarkably consistent early fall weather. Afternoon highs are expected to range from 65 to 70 degrees each day. Friday night will be the coolest of the period, with lows from 45 to 55.
No significant warmup is indicated through Saturday, leaving the Chicago area with seasonably cool conditions during the first several days of astronomical fall.
Residents should keep a light jacket handy for mornings and evenings and watch for isolated showers Tuesday. Along Lake Michigan, Tuesday's high swim risk remains the primary safety concern.
Five Day Weather for Chicago, Illinois
Tuesday: 61 66; a few showers possible. Low 49 58. Wednesday: 65 68; partly cloudy. Low 49 58. Thursday: 65 70; partly cloudy. Low 48 57. Friday: 65 70; partly sunny. Low 45 55. Saturday: 65 70; partly cloudy. Low 48 57.