Massachusetts dense fog advisories
There are no dense fog advisories in Massachusetts right now. The last one was issued on July 1, 2025.
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 Massachusetts
None right now. Other active alerts in Massachusetts: none.
Dense Fog Advisories in Massachusetts by year
Massachusetts averaged 20 dense fog advisories per year from 2016 to 2025. The most recent was issued on July 1, 2025.
Counties with the most dense fog advisories
| County | 2016–2025 |
|---|---|
| Nantucket County | 142 |
| Plymouth County | 140 |
| Bristol County | 138 |
| Dukes County | 137 |
| Barnstable County | 133 |
| Norfolk County | 73 |
| Essex County | 65 |
| Middlesex County | 61 |
| Suffolk County | 57 |
| Worcester County | 44 |
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.