If you're wondering why your favorite stretch of sand didn't make the 2026 best-beaches list from "Dr. Beach," Stephen P. Leatherman likely has a data point for that. The coastal scientist, who has ranked US beaches since 1991, evaluates 650 major public spots using 50 criteria, from water temperature and clarity to sand quality, wave size, cleanliness, rainfall, and even ease of public access at resort-lined shores. Warm "swimming beaches" tend to win out, which helps Hawaii and Florida dominate; chillier New England, Pacific Northwest, and Northern California shores often get passed over as "too cold." Strong tides that cloud the water are another strike—"people want to see their toes," he tells CNN. Pollution, erosion, and seaweed overload can also knock past winners off the list entirely. Without further ado, the top 10: