Twelve city pools, including Sunset Park Pool and the Kosciuszko Pool in Bed-Stuy, will stay open until 8 p.m. through Labor Day, the Parks Department announced Monday, as the city entered its third heat advisory of the summer.

The extended hours add 90 minutes to the evening session, historically the most crowded of the day. Officials said a 9 percent increase in lifeguard staffing, the result of a winter recruiting push and a $21-an-hour starting wage, made the longer schedule possible for the first time since 2019.

At Sunset Park on Monday afternoon, the deck was jammed by 4 p.m. and the line outside stretched past the handball courts. "The evening swim is the whole point," said Gloria Then, 64, who has come to this pool since it reopened in 1984. "You want the water when the sun quits being rude."

Cooling centers remain open at 14 Brooklyn library branches, and the city is again capping fire hydrants with spray nozzles on request; residents can call 311 to borrow one. Forecasters expect highs near 96 through Thursday. Parks officials had one request for evening swimmers: bring a lock. "The lost-and-found," a spokesperson said, "is beyond capacity."