California Code, Labor Code - LAB § 1391

(1) An employer shall not employ a minor 15 years of age or younger for more than eight hours in one day of 24 hours, or more than 40 hours in one week, or before 7 a.m. or after 7 p.m., except that from June 1 through Labor Day, a minor 15 years of age or younger may be employed for the hours authorized by this section until 9 p.m. in the evening.

(2) Notwithstanding paragraph (1), while school is in session, an employer shall not employ a minor 14 or 15 years of age for more than three hours in any schoolday, nor more than 18 hours in any week, nor during school hours, except that a minor enrolled in and employed pursuant to a school-supervised and school-administered work experience and career exploration program may be employed for no more than 23 hours, any portion of which may be during school hours.

(3) An employer shall not employ a minor 16 or 17 years of age for more than eight hours in one day of 24 hours or more than 48 hours in one week, or before 5 a.m., or after 10 p.m. on any day preceding a schoolday. However, a minor 16 or 17 years of age may be employed for the hours authorized by this section during any evening preceding a nonschoolday until 12:30 a.m. of the nonschoolday.

(4) Notwithstanding paragraph (3), while school is in session, an employer shall not employ a minor 16 or 17 years of age for more than four hours in any schoolday, except as follows: