California Code, Education Code - EDC § 46141

The minimum schoolday in a high school is 240 minutes, except in an evening high school, an early college high school, a middle college high school, a regional occupational center, an opportunity school and in opportunity classes, a continuation high school, in continuation education classes, in late afternoon or Saturday occupationally organized vocational training programs conducted under a federally approved plan for vocational education, and for students enrolled in a work experience education program approved under the provisions of Article 7 (commencing with Section 51760) of Chapter 5 of Part 28.