When Does Summer Start 2024 California. Summer begins with the summer solstice, friday, june 20, 2025, 10:42 p.m. Most california school calendars are traditional, and run from fall, through winter, to spring, with summer vacation starting in either may or june.

Is it really the longest day of the year? Most california school calendars are traditional, and run from fall, through winter, to spring, with summer vacation starting in either may or june.