King Tides Are Coming to SF Bay this December & January

Roughly twice a month, when the earth, moon, and sun are aligned, the increased gravitational pull of the sun and moon on our planet’s seas bring what we call “spring tides.” When a full or new moon coincides with “perigee” (when the moon’s elliptical orbit brings it as close to the earth as it can get), the range between high and low tides can be extreme. This phenomenon is known as a perigean spring tide or “king tide.” Occuring about three or four times a year, king tides bring strong tidal currents, extreme low tides that expose mud flats and tidal pools, and sometimes extraordinary shoreline flooding at high tide.

The biggest king tides of the year are coming to the San Francisco Bay Area this December 23-24 and January 21-22. As always, we recommend that sailors check tidal predictions for your local substation before setting out. During king tide phases, extra caution is warranted due to the strong currents and during low tide, risk of running aground in areas that are usually deep enough for safe navigation.

Inspire Sailing will be closed for the holidays during the December king tides, but if you do happen to get on a boat or take a stroll along a San Francisco Bay waterfront, you can expect to see some uncommon and even interesting conditions (and critters!) during the king tides.

The California King Tides Project

The California King Tides Project helps us visualize future sea level by observing the highest tides of today. You can help by taking and sharing photos of the shoreline during king tides to create a record of changes to our coast and estuaries.

Also, there are some fun events and activities organized around king tides, including group waterfront strolls, nature walks, and tidepool explorations.

Find out what time and how high the king tides will be near you.