Chicago, IL – A calm, sunny Sunday morning gives way to an early-week change as Illinois braces for on-and-off rain by Tuesday and cooler air settling in just in time for Halloween. The mild start won’t last long — models hint at a quick drop in temperatures and a damp setup that could turn crisp and windy by Friday night’s trick-or-treat hours.
According to the National Weather Service, highs will reach near 58°F Sunday and 57°F Monday under mostly sunny skies. Clouds build by late Monday, followed by a 40–50% chance of rain Tuesday into Wednesday. Afternoon commuters along I-55 and I-90 could see wet pavement and slower traffic as the system passes. East-southeast winds may gust near 20 mph, adding a brisk edge by midweek.
By Thursday, drier air moves in with highs in the low 50s — perfect for last-minute Halloween prep. Friday’s trick-or-treaters should expect chilly, breezy air in the upper 40s with patchy clouds. Light jackets and reflective gear are recommended for families heading out after sunset.
For weekend planners, Saturday looks partly sunny and cool near 54°F — ideal for cleanup or early winter decorating. Meteorologists say the pattern signals a colder November stretch ahead, with the season’s first flurries possible in early November.
