Pediatricians say teens need 8.5 to 9.5 hours of sleep a night, and that starting school before 8:30am is a public health issue.

Opponents say school schedules should be decided locally — not by the state — and that a web of considerations, from transportation to after-school sports schedules, favor earlier starts.

Driving the news: California’s law — which also sets 8am as the earliest that middle schools can start, and has an exception for rural districts — will affect the state’s three million middle and high school students, who previously had an average start time of 8:07. It has also helped spawn similar legislation in New York and New Jersey.

New York’s bill would go further than California’s, requiring all public schools to start at 830am or later.

New Jersey’s bill would set rules similar to California’s, starting in 2024.