Large area temperature spread ahead Saturday afternoon; season’s coolest air will bring the chance for widespread frost Tuesday

Summer-level warmth returned Friday, including the warmest Oct. 11 in 51 years, thanks to steady southwest winds which overcame lake cooling and pumped in much warmer air across the entire metro area. 

It also marked the 99^th and 102nd days of 80-degrees or warmer temperatures at both major observation sites. 

Mid afternoon Friday temperatures: How much warmer than at the same time Thursday? 

Large area temperature spread ahead Saturday afternoon 

From the low 60s northern suburbs to the lower 80s far south 

Season’s coolest air will bring the chance for widespread frost, especially for areas away from Lake Michigan Tuesday morning and again Wednesday morning. 

Forecast lows Tuesday morning 

Forecast lows Wednesday morning 

Cooler than normal conditions to persist overall on average through October 17 before another major pattern change to much warmer than normal temperatures. 

Forecast temperature anomaly through October 17  

Forecast temperature anomaly October 18 through 24   

Forecast highs next five days: How far from normal?