Chicago seemingly switched from summer to fall overnight.
Temperatures plunged from a high near 80 degrees on Wednesday to the mid-50s on Thursday, and by mid-day the area set a record low for high temps.
On this date in 1940, the coolest high temp was 61 degrees. On Thursday, O'Hare Airport recorded a high of 56 degrees.
And fall hasn't officially started.
Thursday remains mostly cloudy, breezy and cool with brief breaks for sunshine. Low temps are expected to drop to the mid-40s by nighttime with light lake-effect showers developing in northwesst Indiana, then shifting into Cook and Lake counties.
Expect some spotty lake-effect sprinkles or showers Friday morning ahead of light showers developing again in the afternoon from the west.
Conditions remain unseasonably chilly with temps in the upper 50s to low 60s.
Fall-like weather sticks around through the weekend. Rain ends early on Saturday, which is expected to turn partly sunny with continued cool. Highs could reach the low 60s.
Sunday morning sunshine mixes with clouds later in the afternoon as cool temps remain in the mid-60s.
A temperature rebound slowly begins Monday as highs climb into the upper 60s. Tuesday temps could reach the low 70s.