Here's Why San Diego Schools Are Starting Later Than Usual

Thomas Park

If you’re wondering why schools throughout San Diego County — and California at large — are starting their days earlier than in the past, there’s a simple reason why.

Parents likely have already noticed that high school students are seeing their start times pushed to 8:30 a.m.

The switch wasn’t an arbitrary change by San Diego school districts. Instead, it’s a result of a new law passed in 2019 and enacted this school year.

California Senate Bill No. 328

In 2019, the California state legislature passed SB 328, which adds a new section to the Education Code that lays out when schools in the state can start.

The law's text explicitly states that high school students' school day should start no earlier than 8:30 a.m. For middle school students and districts around the state, it’s 8 a.m.

Additionally, the law also includes charter schools operating as either high schools or middle schools.

Although lawmakers passed the bill in 2019, it didn’t officially take effect across California until July 1, 2022.

There are other aspects to the law, including exempting rural school districts and encouraging the State Department of Education to publish information on the impact of sleep deprivation on adolescents.

Some school districts in San Diego began experimenting with a later start time in the 2020 to 2021 academic year. However, as of July 2022, late starts are now required under law throughout California.

The science behind later start timers

California didn’t pass the law to give teenagers and other students an excuse to sleep in. In fact, later start times are grounded in science.

For example, the American Academy of Pediatrics recommends that teenagers need at least 8.5 to 9.5 hours of sleep each night for optimal rest. The CDC and the American Medical Association make similar recommendations.

That's largely because teens generally have a different circadian rhythm than adults or even their younger peers. Around the onset of puberty, teens will generally get a circadian rhythm shift and a later release of melatonin, a hormone that regulates the sleep/wake cycle.

In other words, most teens' sleep/wake cycles will keep them awake until around 11 p.m. Because of that, their natural circadian rhythm won’t actually optimize their brains for learning until at least 8 a.m.

In fact, there’s plenty of evidence that teens are currently in the midst of a sleep deprivation epidemic.

Sleep deprivation among teens is associated with many negative effects, including decreased emotional resiliency, reduced ability to learn, and a reduction in sports performance.

California is the first, but probably won’t be the last

California is the first state in the U.S. to enact a law of this scope, but it likely won’t be the last. As of writing, states like New York and New Jersey are also considering legislation that would mandate later start times.

More than anything, however, experts are looking to California for data on whether the later start times will improve academic performance, grades, and graduation rates. Based on the science, the new law should have a measurable effect.