Maricopa County Parks and Recreation

Lake Pleasant in northwest Maricopa County.

The Memorial Day holiday marks the unofficial start of the summer. And though it may be hot, people aren’t staying inside.

Lake Pleasant-- metro Phoenix's largest lake-– was filled to capacity by noon Saturday. That caused the Maricopa County Sheriff's Office to restrict more vehicles from entering the area.

Other recreational hot spots in the state have also been bracing for crowds.

Rangers at Fossil Creek in Camp Verde utilized a reservation system, and the area is fully booked.

Phoenix-area lakes open today include Bartlett, Apache, and Canyon.

The Associated Press contributed to this report.