Chicago, Illinois – Temperatures will drop into the low to mid-30s late tonight, with a higher risk of widespread frost developing by Friday night into early Saturday, potentially impacting early morning travel and outdoor conditions.
According to the National Weather Service in Chicago, a prolonged cool pattern will keep daytime highs between 50°F and 60°F through Saturday, with cooler readings near Lake Michigan. Overnight lows will fall to 34–42°F tonight, then drop further to 32–37°F Friday night, creating conditions favorable for widespread frost formation.
Areas across the Chicago metro, including I-90, I-94, and I-55 corridors, could see patchy frost on bridges and elevated surfaces during the early morning hours, especially away from the immediate lakeshore. Suburban and outlying areas face the highest risk where temperatures cool more efficiently.
The primary impact is to vegetation. Sensitive plants, gardens, and early crops may be damaged or killed if left unprotected for several hours. Residents should cover plants or bring them indoors before temperatures fall overnight.
Conditions begin to moderate Sunday, with highs rising into the 60s and then 70s by Monday. Frost risk will diminish after Saturday morning, but the cool pattern continues with periodic chances for light showers into early next week.
