GET THE SWEATERS AND LIGHT JACKETS READY–CHICAGO IS HEADED FOR ITS COOLEST DAYTIME TEMPS IN THE 4-MONTHS SINCE THIS PAST MAY–A 15 to 20-DEG PULLBACK BETWEEN WED AND TOMORROW AFTERNOONS–MORNING TEMPS SLATED FOR A 20+-DEG PULLBACK BY DAYBREAK THURSDAY–INCOMING “NNW” WINDS TO CHURN LAKE MICHIGAN WITH WAVES & RIP CURRENTS TO BUILD—AND WEEKEND WARMING TO GIVE WAY TO STILL COOLER AIR BY/DURING EARLY/MID NEXT WEEK.

The AUTUMNAL EQUINOX–the astronomical beginning of the 2022 fall season—takes place at 8:04 tomorrow (Thursday) evening. A temp drop will have taken place before that. The first back-to-back daytime 60s–plus the coolest high temp— since May are on the way. Northwesterly wind gusts are to build, and even exceed, 30 mph at times–and nowhere more than along and out over Lake Michigan where waves are to build and rip currents are to develop. A BEACH HAZARDS STATEMENT has been issued from late tonight through late Thursday night as a result. 

I’ve put up a series of LAKE MICHIGAN WAVE HEIGHT GRAPHICS so you can follow model projections of how waves will build on Lake Michigan through Thursday with the gusty NNW winds which are on the way.
SO, WHAT DOES WEATHER HISTORY IN CHICAGO TELLS US ABOUT FUTURE WARM TEMP PROSPECTS
Warm weather is hardly over despite short term cooling.

I asked my WGN meteorological colleague Mark Carroll to check into 80s and 90s beyond this date (Sept 21)—-and also the historic occurrence of 32-deg and sub-32-deg temps over the coming 30 days (through Oct 21)–and what Mark found is interesting:

Number of years since 1871 (the past 151 years) with high temps of:80-deg or warmer: 82%90-deg or warmer: 11%
32-deg TEMPS: 2/3’s of the past 151 years HAVE NOT HAD A FREEZING TEMP AT ALL in the 30 days following Sept 21. So, from a climatological standpoint, we’re hardly at the precipice of full intensity cold air.

But cool spells will grow more frequent–punctuated by warm spells like that expected by Saturday afternoon.