SAN FRANCISCO — A Coastal Flood Advisory is in effect for San Francisco through Thursday afternoon as a run of unusually high tides combines with forecast surge along the Bay shoreline.
The National Weather Service says up to 1.2 feet of inundation above ground level is possible in low-lying areas near shorelines and tidal waterways. The risk is localized rather than a warning that the whole city will flood.
What time is high tide in San Francisco?
| Day | Forecast high tide | San Francisco gauge level |
|---|---|---|
| Monday, Sept. 28 | 12:57 p.m. | 6.87 ft MLLW |
| Tuesday, Sept. 29 | 1:30 p.m. | 7.01 ft MLLW |
| Wednesday, Sept. 30 | 2:10 p.m. | 7.03 ft MLLW |
| Thursday, Oct. 1 | 2:58 p.m. | 6.92 ft MLLW |
NWS says each of those San Francisco tidal-gauge peaks is expected to run about 1.2 feet above normal. The forecast includes as much as 0.7 feet of surge on top of the astronomical tide.
Timing can differ around the shoreline. NWS says high tide may occur as much as 90 minutes earlier or later along the Pacific Coast and through San Francisco Bay, depending on location.
Which day has the highest tide?
Wednesday afternoon is the highest of the four San Francisco gauge forecasts, at 7.03 feet MLLW around 2:10 p.m. Tuesday is close behind at 7.01 feet.
That does not mean flooding is guaranteed at a particular street or park. Actual impacts depend on local elevation, shoreline exposure and conditions at the time of high tide.
What could flood during the advisory?
NWS says the most likely impacts are in low-lying shoreline and tidal areas. Its advisory specifically mentions flooding of lots, parks and roads, with isolated road closures possible.
High water can also cover coastal trails, restrict access to some low-lying beaches and push water and waves farther up the beach than usual.
Is all of San Francisco under a flood threat?
No. The advisory includes San Francisco as a forecast zone, but the described hazard is concentrated near shorelines and tidal waterways. Inland neighborhoods are not being told to expect 1.2 feet of water.
That distinction matters for anyone seeing a citywide weather alert on a phone. The practical concern is whether your route, parking area, trail or waterfront destination is low enough to be affected near the afternoon tide peak.
Why are the tides unusually high?
The Weather Service describes an astronomical high tide enhanced by forecast surge. Its San Francisco predictions include up to 0.7 feet of surge, which raises the water level above what the astronomical tide alone would produce.
SF News Today is not labeling this a “king tide” because the current NWS advisory does not use that term. The useful point is simpler: the expected water level is running well above normal for several afternoons in a row.
Could roads or trails close?
Yes, but NWS expects any road closures to be isolated. The agency has not published a block-by-block San Francisco closure list with this advisory, so specific intersections should not be treated as closed unless the city or another responsible agency posts a current notice.
For current city conditions, check SF News Today Live and the weather desk before a waterfront trip.
What should drivers and pedestrians do?
NWS advises allowing extra travel time if a route may pass through a flood-prone area. Drivers should not go around barricades or enter water when the depth is unknown.
People walking shoreline trails should also be prepared to turn around if water covers a low section or access point. Conditions near the high-tide window can look very different from the same place a few hours earlier.
When does the Coastal Flood Advisory end?
The current advisory runs until 5 p.m. Thursday, Oct. 1. Because weather advisories can be extended, replaced or canceled, anyone making plans later in the week should check the latest NWS product again before traveling.