These numbers come from two offshore buoys: Monterey Canyon Outer (46236) for the bay sites and Point Sur (46239) for the Carmel side. They measure the open ocean, not the beaches, so each site's rating adjusts them for that spot:
- Swell direction Every site has its own window of directions it's open to. Headlands like Point Pinos, Cypress Point and Point Lobos block swell from some directions, so the same swell can hit one beach at full strength and barely reach another.
- Swell period Longer-period swell carries more energy and bends around points more, so it reaches sheltered sites more and produces deeper surge than short-period swell of the same height.
- Several swells at once The buoys often see two or three swells from different directions, and each is weighed against the site's exposure before they're combined.
- Wind Onshore wind at a site adds chop and makes entries harder; offshore wind usually smooths the surface until it gets strong. Wind is from the National Weather Service forecast for each site.
- Site rules Each site has its own limits, its own onshore wind direction and its own tide rules. Monastery and Carmel River get stricter limits because their shore break turns dangerous quickly, the Breakwater reads rougher when a high tide of 5 ft or more meets the swell, and extreme low tides count more at the Point Lobos ramp, Bluefish and Coral Street.
- Forecast check The wave forecast is compared with what the buoys actually measured and corrected when it runs high or low.
The buoys sit offshore, so "Waves" on each card is an estimate for that site. Always look at the water before you get in.