About

COSMOS (California State Summer School for Mathematics & Science) is California’s flagship state-funded STEM summer program for high school students. Established in 1999, it offers a four-week, residential academic experience at UC campuses (UC Santa Cruz, Davis, Irvine, San Diego, and recently UCLA). Tuition is about $5,000–$6,000, but California residents often receive state subsidies and need-based aid, making COSMOS one of the most valuable bang-for-your-buck STEM programs available.

Each summer, COSMOS enrolls about 800–1,000 students statewide across its UC campuses. Acceptance percentages vary by campus and cluster, but the overall admit rate hovers around 20–25%. This can be deceiving, however—some of the most popular STEM clusters have acceptance rates at 10% or lower.
Admissions decisions are cluster-specific: applicants rank research clusters (e.g., bioengineering, computer science, astrophysics) at a single UC campus when filling out their applications, which require essays, transcripts, and recommendations. California residency is required.

Students live in UC dorms and spend four weeks immersed in a cluster-based curriculum, combining lectures, labs, and project-based research. Each cluster is taught by UC faculty, postdocs, or graduate students, and the experience culminates in team poster presentations. COSMOS emphasizes both hands-on lab work and collaborative learning, and the residential setting fosters a strong peer community across clusters.

For California students targeting the UC system, COSMOS is genuinely valuable: UC admissions officers recognize the program as a rigorous, state-backed credential, and the UC application takes specific note of COSMOS. Alumni often highlight COSMOS in UC application essays, and participation can strengthen competitiveness for any relevant STEM major. While not as prestigious as the nation’s top-tier STEM programs, COSMOS offers an excellent academic experience—although students should not expect the in-depth laboratory research they’d find at RMP or SIP.