Chicago gets one relatively calm day Friday before a stormier pattern is expected to take over the weekend. Skies should start mostly clear, with temperatures around 66 degrees early and a high near 69. Partly sunny conditions and east-northeast winds of 10 to 15 mph are expected.
Lake Michigan hazards return before the rain
Rain chances should remain minimal through Friday afternoon, but clouds are expected to thicken overnight. A Beach Hazards Statement remains in effect for Chicago-area beaches through 3 p.m. Friday, with waves of 3 to 6 feet and dangerous currents possible.
Swimming in those conditions can be life-threatening. Beachgoers should also stay off piers, jetties, breakwalls and other shoreline structures. The National Weather Service Great Lakes safety guidance says dangerous currents and breaking waves are common in the region and that shoreline structures can intensify the danger.
Storms are most likely Saturday
Showers and thunderstorms are expected after 1 a.m. Saturday, with a 60% chance of rain and possible totals between a quarter-inch and a half-inch. Saturday could be the wettest day of the weekend: thunderstorms are likely before 7 a.m. and may continue through the day, with a high near 72 and a rain chance listed at 100%.
Showers and thunderstorms may continue Saturday night and Sunday. Sunday's high is expected to reach only about 68 degrees. Periods of heavy rain could produce localized flash flooding, especially if downpours repeatedly move across the same areas. That is a forecast risk, not a report that flooding has already occurred during this event.
Recent Chicago-area storms show why rainfall placement matters
The National Weather Service Chicago documented a separate July 25, 2025, storm in which a slow-moving line of storms caused flash flooding across parts of Chicago. Midway Airport recorded 3.25 inches of rain that day, including 3.14 inches between 11 a.m. and 2:30 p.m., according to the agency's event summary.
Another separate event on Sept. 17, 2023, produced significant flash flooding in Calumet City, Dolton, Burnham and nearby communities. The National Weather Service reported 4 to 6 inches of rain in parts of southern Cook County and extreme northwest Lake County in Indiana in its summary of that flooding event.
Those incidents are useful examples of how quickly localized flooding can develop when intense rain stalls or follows the same path. They occurred on different dates and are not evidence that this weekend will produce comparable totals, impacts or frequency of flooding.
Annual rainfall averages provide broad context
For longer-term perspective, the National Weather Service Chicago's annual precipitation records list Chicago's normal annual precipitation as 37.86 inches, based on official records from 1871 through 2022. That climate average does not determine whether this storm system will be unusually severe and does not establish a trend in the frequency or intensity of heavy rain.
Cooler, windier weather follows
The unsettled pattern may persist Monday, when showers and thunderstorms are possible along with a high near 63 degrees and northeast winds around 20 mph. Tuesday should remain mostly cloudy with a chance of rain showers and a high near 62. Partly sunny, drier weather is expected to return Wednesday and Thursday.
