Not every vessel is shown — only large commercial ships (those on the SF Bar Pilots board) and selected other boats (pilot boats, ferries, tour boats, tugs). Recreational boats, kayaks, some fishing boats and many other small craft won't appear.
Marine Advisories · SF Bay
NWS ↗
SF Bay Swims & Sailing
Swims should only be planned and organized by knowledgeable, experienced individuals who independently assess conditions and safety. Use at your own risk.
Tidal Currents
NOAA ↗
Harmonic stations (mostly SFB…) have their own prediction model, built from weeks to months of current measurements taken at that exact spot, often at several depths. The other (subordinate) stations, mostly PCT…, are typically older sites where too little data was collected for a model of their own: NOAA takes a nearby reference station's predictions and applies fixed time and speed corrections. That's an approximation of the local current, so harmonic stations are usually the more accurate choice.
+ next 2 days
Location for currents data
Wind · Alcatraz Island
Windfinder ↗
SF Weather · 3-Day