San Mateo County, California weather alerts
No watches, warnings or advisories are in force for San Mateo County.
Checked Sun, Sep 20, 2026, 8:49 AM PDT. Times are Pacific Daylight Time.
Warnings on the map
Every watch, warning and advisory the National Weather Service has in force over San Mateo County, California. Open it for the live map, where it pans and zooms.
Open the live map with warnings and watches
Map layer from NOAA National Weather Service. Boundaries from the Iowa Environmental Mesonet.
Alerts in force
Nothing is in force for San Mateo County right now. Its warnings come from the National Weather Service and appear here within a minute of being issued; every one of the past year is below.
The past year in San Mateo County
In the past year the National Weather Service issued 104 alerts for San Mateo County, including 5 severe thunderstorm warnings, 3 flash flood warnings, 3 high wind warnings and 2 tornado warnings.
| Product | Issued | Most recent |
|---|---|---|
| Severe Thunderstorm Warning | 5 | Dec 25, 2025 |
| Flash Flood Warning | 3 | Dec 25, 2025 |
| High Wind Warning | 3 | Dec 24, 2025 |
| Tornado Warning | 2 | Jan 5, 2026 |
| Coastal Flood Warning | 1 | Jan 2, 2026 |
| Red Flag Warning | 1 | Aug 28, 2026 |
| Extreme Cold Watch | 1 | Jan 9, 2026 |
| Flood Watch | 1 | Dec 23, 2025 |
| High Wind Watch | 1 | Dec 23, 2025 |
| Flood Advisory | 20 | Feb 17, 2026 |
| Coastal Flood Advisory | 10 | Sep 8, 2026 |
| Wind Advisory | 8 | May 17, 2026 |
| Dense Fog Advisory | 6 | Feb 26, 2026 |
| Heat Advisory | 6 | Sep 8, 2026 |
| Cold Weather Advisory | 4 | Feb 20, 2026 |
| High Surf Advisory | 4 | Feb 18, 2026 |
| Beach Hazard Statement | 28 | Sep 4, 2026 |
Warnings issued
- Red Flag Warning
- Tornado Warning
- Coastal Flood Warning
- Severe Thunderstorm Warning
- Tornado Warning
- Severe Thunderstorm Warning
- Flash Flood Warning
- Flash Flood Warning
- Severe Thunderstorm Warning
- Severe Thunderstorm Warning
- Flash Flood Warning
- High Wind Warning
- Severe Thunderstorm Warning
- High Wind Warning
- High Wind Warning
Every alert, most recent first
- Coastal Flood Advisory
- Heat Advisory
- Beach Hazard Statement
- Red Flag Warning
- Heat Advisory
- Coastal Flood Advisory
- Beach Hazard Statement
- Heat Advisory
- Coastal Flood Advisory
- Beach Hazard Statement
- Beach Hazard Statement
- Beach Hazard Statement
- Coastal Flood Advisory
- Heat Advisory
- Beach Hazard Statement
- Beach Hazard Statement
- Beach Hazard Statement
- Beach Hazard Statement
- Beach Hazard Statement
- Wind Advisory
- Wind Advisory
- Beach Hazard Statement
- Beach Hazard Statement
- Heat Advisory
- Dense Fog Advisory
- Cold Weather Advisory
- High Surf Advisory
- Cold Weather Advisory
- Flood Advisory
- Flood Advisory
- Coastal Flood Advisory
- Beach Hazard Statement
- Dense Fog Advisory
- High Surf Advisory
- Beach Hazard Statement
- Coastal Flood Advisory
- Beach Hazard Statement
- Beach Hazard Statement
- Beach Hazard Statement
- Cold Weather Advisory
The 40 most recent of 104.
From the Iowa Environmental Mesonet’s archive of NWS watches, warnings and advisories (VTEC), by the county’s own code and the forecast zones inside it. Each date links to the event at the IEM.
Nearby
The counties around San Mateo County, with what is in force in each.
What this means
- Warning
- The hazard is happening or about to. Act now: a tornado warning means take shelter, a flash flood warning means move to higher ground.
- Watch
- Conditions favor the hazard. Nothing is happening yet; have a plan and be ready to act if a warning follows.
- Advisory
- A hazard that is less serious than a warning but can still cause trouble, such as dense fog, heat or light ice.
- Statement
- Information about weather that does not yet meet a warning: a strong storm, a hydrologic update, or a special weather statement.
Severity (extreme, severe, moderate, minor) is the rating the issuing office gives each product. More on the difference: tornado watch vs. tornado warning. Alerts come from the National Weather Service; follow its instructions and your local officials.
Sources
Alerts from the National Weather Service's public feed, read afresh every minute, and matched to counties and zones by their UGC codes. Warnings from outside the United States come from each country's own meteorological service. Follow the issuing office's instructions and your local officials.