Chicago weather: High waves, dangerous swimming conditions and a cool start to the week

Forecasters Sunday said Chicagoans could expect temperatures in the 70s for the latter half of the weekend, a lucky break for those who might otherwise cool off in Lake Michigan when temperatures climb.

That’s because as of Saturday night, swimming was prohibited on all of Chicago’s beaches.

The National Weather Service warned Sunday of dangerous swimming conditions across Chicago’s lakeshore due to high waves. The agency also issued a small craft advisory. Both advisories were in place through early Monday morning.

In the Chicago area, waves as high as 3 to 6 feet may pummel the shores of Lake Michigan, said National Weather Service meteorologist Ricky Castro. The high waves are caused by northerly winds blowing down the length of Lake Michigan.

“And when you get large waves,” Castro said, “that causes large currents, too.”

Warning of the dangerous waves and currents, the weather service posted on social media early Sunday: “Stay dry when waves are high!”

Castro expressed concern that people might travel to unguarded beaches in order to swim. One of the deadliest summer hazards, he said, was dangerous swimming conditions that cause drownings.

In Chicago, cooler weather will continue with temperatures staying in the 70s through Monday. Things will start warming up Tuesday, especially inland, with temperatures rising to the upper 80s by the end of the week.

“It’s going to be a long, dry week,” Castro said. Thunderstorms are not expected to make an appearance until Saturday at the earliest.

Visit the Tribune’s weather page for more information, and check back for updates.