California State Summer School for Mathematics and Science (COSMOS)

COSMOS is a four-week residential University of California summer program for California high-school students. Each student joins a cluster combining two science or mathematics courses, a science-communication course, hands-on laboratories, field activities, faculty lectures and discussion, and a related research project. Official program information says clusters typically enroll 20–25 students and commonly operate near a 5:1 student-to-faculty ratio. In 2026, six UC campuses ran sessions from July 5 through July 31 or August 1.