The Glass

Coastal Waters Forecast issued by NWS San Francisco Bay Area (KMTR), refreshed several times daily. Two zones: PZZ530 covers the north end of the bay, San Pablo, Suisun, and the West Delta; PZZ531 covers the bay south of the Bay Bridge. Showing the next two forecast periods per zone — click through for the full extended outlook and any active small-craft or gale advisories.

Tide heights relative to MLLW (Mean Lower Low Water). San Francisco Bay tides are mixed semidiurnal — two unequal highs and two unequal lows per lunar day. Predictions from NOAA harmonic constants; observations from the Pier 22½ acoustic gauge.

Tidal currents at the Golden Gate run roughly twice daily, mirroring the bay's tide cycle. Flood (incoming, NE 052°) and ebb (outgoing, SW 238°) can exceed 5 knots on spring tides — among the strongest tidal currents on the US West Coast. Slack water windows are short. Predictions from NOAA harmonic constants for station SFB1202 at 21 ft depth.