Iowa dense fog advisories
There are no dense fog advisories in Iowa right now. The last one was issued on September 30, 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 Iowa
None right now. Other active alerts in Iowa: none.
Dense Fog Advisories in Iowa by year
Iowa averaged 73.8 dense fog advisories per year from 2016 to 2025, and has had 53 so far in 2026. The most recent was issued on September 30, 2026.
Counties with the most dense fog advisories
| County | 2016–2025 |
|---|---|
| Osceola County | 122 |
| Lyon County | 119 |
| O'Brien County | 117 |
| Sioux County | 115 |
| Lucas County | 112 |
| Dickinson County | 111 |
| Marion County | 110 |
| Jones County | 109 |
| Clarke County | 109 |
| Jackson County | 109 |
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.
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