The National Weather Service on Wednesday issued a severe thunderstorm warning for the Chicago area, cautioning of the risk of quarter-sized hail and wind gusts of 70 mph.
The thunderstorm watch covers 12 counties in Illinois, including Cook, DuPage, Kane and Will. It also includes two counties in northwest Indiana — Lake and Porter. The weather service said tornadoes were possible.
As storms rolled in Wednesday night, ComEd reported a few thousand customers were without power in DuPage County. There were also scattered outages affecting hundreds of customers on the city’s Far South Side and south suburbs.
Measured wind gusts to 53 mph were observed at both O'Hare and Midway airports! Expect localized wind gusts up to 60-65 mph embedded within this line of storms as it moves through Cook County over the next 20-40 minutes. #ILwx https://t.co/WH5ryDwMNr
— NWS Chicago (@NWSChicago) July 16, 2025
Chicago-area officials have been bracing for summer storms, with flash flooding risk remaining high across several parts of the country. A month’s worth of rain fell in 90 minutes just west of the United Center last week, for example.
“Slow-moving thunderstorms with torrential rain are a frequent trigger for flash flooding in the United States, especially during the warmer summer months when the amount of moisture in the atmosphere peaks,” said Dan DePodwin, vice president of forecast operation for AccuWeather.
“There is a clear trend showing that both the frequency and intensity of summer thunderstorms capable of producing flash flooding have increased in recent decades.”
The Illinois Environmental Protection Agency also issued an Air Pollution Action Day for the greater Chicago area through Wednesday night, meaning widespread ozone levels are expected to be above what is considered safe for certain groups. Children and adults, particularly those with pulmonary or respiratory disease such as asthma, should limit prolonged outdoor activity, the weather service said.
A high temperature near 88 was expected Wednesday afternoon with a 60% chance of precipitation. The heat index value, which is essentially how hot it actually feels, is in the high 90s. Scattered showers and thunderstorms may continue until 11 p.m., the weather service said.
