Weather
Chicago, IL Weather Today: Frost Tonight, Then 70s Next Week Oct 17-20
Chicago, IL – Another cold autumn night is approaching northern Illinois, with temperatures expected to fall into the lower 30s in some communities late Saturday, October 17, prompting Frost Advisorie
By Rachel Monroe · 2026-10-17T09:50:21.775Z
Chicago, IL – Another cold autumn night is approaching northern Illinois, with temperatures expected to fall into the lower 30s in some communities late Saturday, October 17, prompting Frost Advisories and concerns about damage to sensitive outdoor plants.
According to the National Weather Service in Chicago, patchy frost is expected late Saturday night into early Sunday morning, particularly across areas east of Interstate 55 and south of Interstate 80 in Illinois, along with portions of northwest Indiana.
Frost Advisory Issued for Parts of Illinois
Forecasters expect the coldest temperatures along and south of Interstate 80, where overnight readings could fall into the low to mid 30s.
Communities near Kankakee and Pontiac are among those in the advisory area, while locations closer to Chicago and Lake Michigan should remain somewhat warmer.
Chicago and nearby lakeshore communities are expected to see temperatures closer to the lower 40s.
The National Weather Service advises residents to protect tender vegetation by covering sensitive outdoor plants or bringing potted plants indoors before temperatures fall overnight.
Cool Saturday Before Temperatures Rebound
Saturday's afternoon highs will range from 54 to 58 degrees across the Chicago forecast region, followed by overnight lows between 32 and 42 degrees.
Sunday, October 18, will bring sunshine and breezy conditions, with temperatures recovering into the 61 to 64 degree range.
The warming trend continues Monday, with highs reaching 66 to 71 degrees.
Temperatures Could Reach 76° by Wednesday
By Tuesday, October 20, afternoon temperatures are forecast to climb between 70 and 74 degrees.
Wednesday could be even warmer, with highs reaching 72 to 76 degrees across portions of the region.
Locations near Lake Michigan may remain cooler, with temperatures generally in the mid to upper 60s.
Residents should take precautions against frost Saturday night before a noticeable return to above normal warmth early next week.