Chicago and Rockford reportedly reached the mid- to upper 80s on Monday, surpassing temperature marks set in 2008 for that calendar date. Final readings for the two cities were not available in the detailed account.

In Chicago, the National Weather Service measured 83 degrees by 1 p.m. Meteorologist Jake Petr projected a high of 86 degrees at O’Hare Airport, where the Oct. 12 mark was 84 degrees.

Tuesday could bring similar warmth, though its Oct. 13 mark stands at 88 degrees. Petr said thunderstorms, with a small chance of hail, could arrive Tuesday night before a cold front brings cooler weather Wednesday. More showers were expected Thursday.