Real-time surface currents in San Francisco Bay are updated hourly here. Movies of currents will also be available for download soon (see example at bottom of page).
 
How to read these maps:
Arrow lengths and size indicate direction and magnitude of water flow at the surface.  Colors correspond to current speeds in cm/s, the legend is shown at right.
 
SF Bay
Hourly Surface Current Map
To download data from SF Bay, link to the Data page.
Date above is in GMT time; to convert to Pacific Daylight Time (PDT), subtract seven hours. To convert to Pacific Standard Time (PST), subtract eight hours.  To download image above: PC users right click; Macs users press “control+click” to download to disk.