Chicago-area residents will have to break out their stocking caps and heavy coats as a freeze warning impacts the region this week.
The coldest air of the season has already arrived, dropping temperatures below their normal levels and paving the way for the first sub-freezing temps of the fall during the overnight hours.
Here’s everything you need to know.
What areas will be most affected?
According to the National Weather Service, a freeze warning has been issued for McHenry, DeKalb, Kane, LaSalle, Kendall and Grundy counties. That warning goes into effect at 1 a.m. and will last through mid-morning Wednesday.
Northern Cook County, Will County and Kankakee County are all under a frost advisory Wednesday morning, with slightly warmer temperatures potentially helping to avoid a hard freeze.
When will the coldest temperatures occur?
Local
According to the National Weather Service, the coldest temperatures will occur just before daybreak on Wednesday, with lows in the upper-20s in the western suburbs.
In parts of the area impacted by the frost advisory, lows will likely settle around 30 degrees, and will slowly start to warm after daybreak.
Feeling out of the loop? We'll catch you up on the Chicago news you need to know. Sign up for the weekly Chicago Catch-Up newsletter.
Is this type of cold normal at this time of year?
Indeed it is. In fact, according to the National Weather Service, the typical first freeze of the fall occurs in mid-October for most of the Chicago area, ranging between Oct. 11 and Oct. 20.
The exact normal date for the first freeze in Chicago is Oct. 19, with areas closer to the lake seeing that date slide into the last week of the month or even into the first week of November due to the proximity to Lake Michigan.
For the rest of the suburbs, the first freeze typically occurs earlier, occurring around Oct. 13 in Rockford.
In 2023, Chicago’s first sub-freezing temperature didn’t occur until Oct. 30, when the low temperature was 31 degrees. The following day, the city saw nearly an inch of snow, its first measurable snowfall of the season.
How long will the cold temps last?
For those residents who aren’t thrilled about the cold, the good news is that it won’t last long. Temperatures will still be on the cool side Wednesday, with highs in the mid-to-upper 50s, but a warming trend will really get underway on Thursday.
Temperatures will rise back into the 60s for Thursday, and by Saturday highs will be back into the 70s across the area, with nighttime lows in the upper-40s and low-50s, according to forecast models.
Those conditions are expected to stick around for several days, with partly-to-mostly sunny conditions expected.
What about the rain?
Lake-effect rain could last into the overnight hours in the Chicago area, but will slowly start to drift to the east as winds begin to shift, blowing the moisture plume away from the city.
After it moves out, it is expected to be mostly dry for several days, with no sustained chances of rain in the extended forecast at this time.
