Chicago is set for a bright and unusually warm Saturday, with mostly sunny skies and temperatures climbing to about 86F (30C), according to forecasters.
Fox Chicago meteorologist Mark Strehl said the city began September 12, 2026, with clear conditions and no immediate threat of rain. The National Weather Service forecast a dry day, with temperatures rising steadily through the afternoon and only a slight chance of precipitation.
The warmth will be well above the usual mid-September average of roughly 77F (25C). Temperatures are expected to peak during the afternoon before easing into the low 60s overnight, while skies become partly cloudy.
Chicago weather set to turn cooler on Sunday
Conditions are expected to change on Sunday, when the National Weather Service is forecasting a high of about 72F (22C), with partly sunny skies giving way to a chance of scattered showers, particularly during the afternoon.
Monday should remain mostly sunny and similarly cool, but the unsettled pattern is expected to return on Tuesday. Forecasters are warning of possible showers and thunderstorms, with temperatures rising again to around 84F (29C) and humidity increasing across parts of the region.
The sharp changes in temperature are likely to continue into the middle of next week, creating the “bit of a temperature roller coaster” highlighted by the National Weather Service.
