California dense fog advisories
There are no dense fog advisories in California right now. The last one was issued on November 11, 2026.
Fog will reduce visibility to a quarter mile or less, making driving hazardous.
Updated from the National Weather Service · lists refresh hourly; the live map loads current alerts directly from the NWS
Map data: NWS, OpenFreeMap, OpenStreetMap
Active dense fog advisories in California
None right now. Other active alerts in California: 19 (see the California alerts page).
Dense Fog Advisories in California by year
California averaged 117.7 dense fog advisories per year from 2016 to 2025, and has had 85 so far in 2026. The most recent was issued on November 11, 2026.
Counties with the most dense fog advisories
| County | 2016–2025 |
|---|---|
| San Joaquin County | 338 |
| Santa Barbara County | 214 |
| San Luis Obispo County | 166 |
| Los Angeles County | 148 |
| San Diego County | 145 |
| Ventura County | 128 |
| Orange County | 126 |
| Sacramento County | 118 |
| Kern County | 59 |
| Tulare County | 59 |
What a dense fog advisory means
Dense fog can cause chain-reaction crashes on highways because drivers suddenly lose sight of the road ahead.
More about dense fog advisories and the national map →
What to do
- Slow down, use low-beam headlights and leave plenty of distance.
- Never use high beams in fog.