There is no uniform standard for when California public schools begin the academic year. Some school districts in the state begin in mid-August while others do not start until after Labor Day.
Public and private schools in California generally operate from autumn until spring of the following year with a summer break in between sessions. A few schools operate on a year-round schedule in which students continue to attend classes during the summer. School districts are administratively separate from each other, and each one has some wiggle room to determine the specific days the academic year begins and ends. Check the calendar of the local school district to confirm its schedule.