1 warning and 1 advisory are in effect for San Mateo County, CA. The most serious is a coastal flood advisory.
Since 2016 the National Weather Service has issued about 196 alerts that included San Mateo County, roughly 20 a year. The most common is the flood advisory (143 from 2016 to 2025). The last tornado warning was issued on January 5, 2026. 4 tornadoes have touched down in the county since 1950.
Updated from the National Weather Service · lists refresh hourly; the live map loads current alerts directly from the NWS
San Francisco; Coastal North Bay Including Point Reyes National Seashore; San Francisco Peninsula Coast; Northern Monterey Bay; Southern Monterey Bay and Big Sur CoastUntil · NWS San Francisco CA
HIGH SURF WARNING REMAINS IN EFFECT UNTIL 4 AM PST SUNDAY... ...COASTAL FLOOD ADVISORY REMAINS IN EFFECT UNTIL 6 PM PST THIS EVENING
Full alert text
* WHAT...For the High Surf Warning, dangerously large breaking
waves of 25 to 35 ft, with occasional sets of 40 to 50 ft at
favored breakpoints. For the Coastal Flood Advisory, large
breaking waves will run up beaches and crash over seawalls,
inundating adjacent, low-lying infrastructure.
* WHERE...All Pacific Coast Beaches.
* WHEN...For the High Surf Warning, until 4 AM PST Sunday. For the
Coastal Flood Advisory, now through 6 PM PST today.
* IMPACTS...High tides will result in flooding of low-lying
infrastructure, isolated road closures, and coastal erosion.
Rising tides will bring water and waves farther up the beach
than normal, restricting escape from beaches and coastal
areas. Dangerously large breaking waves can overpower
swimmers, pulling people into the sea from beaches, jetties,
and rocks resulting in significant physical injury and
increasing the risk of drowning. Waves can sweep across the
shoreline without warning, pulling people into the sea from
beaches, jetties, and rocks.
* ADDITIONAL DETAILS...The Coastal Flood Advisory today is
specifically for the Pacific Coast, where large breaking waves
will spill over sea walls and run up beaches onto adjacent
infrastructure.
What to do: If travel is required, allow extra time as some roads may be
closed. Do not drive around barricades or through water of
unknown depth. Take the necessary actions to protect flood-prone
property.
Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.
High Surf Warning
San Francisco; Coastal North Bay Including Point Reyes National Seashore; San Francisco Peninsula Coast; Northern Monterey Bay; Southern Monterey Bay and Big Sur CoastUntil · NWS San Francisco CA
HIGH SURF WARNING REMAINS IN EFFECT UNTIL 4 AM PST SUNDAY... ...COASTAL FLOOD ADVISORY REMAINS IN EFFECT UNTIL 6 PM PST THIS EVENING
Full alert text
* WHAT...For the High Surf Warning, dangerously large breaking
waves of 25 to 35 ft, with occasional sets of 40 to 50 ft at
favored breakpoints. For the Coastal Flood Advisory, large
breaking waves will run up beaches and crash over seawalls,
inundating adjacent, low-lying infrastructure.
* WHERE...All Pacific Coast Beaches.
* WHEN...For the High Surf Warning, until 4 AM PST Sunday. For the
Coastal Flood Advisory, now through 6 PM PST today.
* IMPACTS...High tides will result in flooding of low-lying
infrastructure, isolated road closures, and coastal erosion.
Rising tides will bring water and waves farther up the beach
than normal, restricting escape from beaches and coastal
areas. Dangerously large breaking waves can overpower
swimmers, pulling people into the sea from beaches, jetties,
and rocks resulting in significant physical injury and
increasing the risk of drowning. Waves can sweep across the
shoreline without warning, pulling people into the sea from
beaches, jetties, and rocks.
* ADDITIONAL DETAILS...The Coastal Flood Advisory today is
specifically for the Pacific Coast, where large breaking waves
will spill over sea walls and run up beaches onto adjacent
infrastructure.
What to do: If travel is required, allow extra time as some roads may be
closed. Do not drive around barricades or through water of
unknown depth. Take the necessary actions to protect flood-prone
property.
Everyone should remain out of the water due to life-threatening
surf conditions. Stay off of jetties, piers, and other waterside
infrastructure.
Map data: NWS, OpenFreeMap, OpenStreetMap
Recent alerts in San Mateo County
Issued
Alert
Area
Nov 14, 4:05 AM EST
Coastal Flood Advisory
San Francisco; Coastal North Bay Including Point Reyes National Seashore; San Francisco Peninsula Coast; Northern Monterey Bay; Southern Mon
San Mateo County alert history
Alert events that included San Mateo County or its forecast zones, from the NWS warning archive.
4 tornadoes have been recorded in San Mateo County since 1950. That ranks 30 of 58 counties in California. The most recent was on March 20, 2005 (rated F1).