It’s a sign of the official start of summer in Chicago.

On Friday, all 22 of the city’s beaches will open, the Chicago Park District said.

The end of the open beach season will be Labor Day, on Sept. 1.

Park District General Superintendent and CEO Carlos Ramirez-Rosa said the city’s recruitment efforts last year resulted in more than 2,800 applications for lifeguard positions, above the city’s goal.

“Our well-trained lifeguard team will be on duty to provide increased public safety and enriching summer experiences for all visitors enjoying Chicago’s majestic beaches this season,” he said in a statement.

The lifeguards are in the process of completing their required training before the beaches open. The Park District is still accepting applications for the final swim test on May 31.

Security units, including six prominently marked vehicles, will also be deployed to patrol the lakefront daily from 11 a.m. to 7 p.m. starting on Friday.

Newly refreshed signs telling visitors to “Swim Only When Lifeguards are on Duty,” “No Diving,” and “No Swimming” will be visible along the lakefront, the Park District said.

Flags indicating the swim status of the lake will also be used again. 

Green flags mean swimming is permitted, weather conditions are fair, and water quality is good.

Yellow flags mean swimming is permitted, but visitors are advised to be cautious. Weather conditions are unpredictable, or bacteria levels may be higher than the water quality criteria set by the EPA for notifying the public.

Red flags mean swimming is not permitted, and that weather conditions or water quality conditions are dangerous.

For more information about beach safety and rules, visit ChicagoParkDistrict.com/beaches.