Tell it where the wind's blowing from and it ranks every harbor by how sheltered you'll be — so you head for the few good options tonight, not scroll through forty. The protection nobody else computes.
In a southwest wind: 32 good · 8 fair to tuck into.
Protection ratings are computed from shoreline fetch and cross-checked against the Coast Pilot — a planning aid, not a forecast. Always check the marine forecast and your own eyes before you commit to a night at anchor.