National Weather ServiceWisconsinDense Fog AdvisoryArchive to October 1, 2026
Dense Fog Advisories in Wisconsin
The National Weather Service issued 89 dense fog advisories for Wisconsin in 2025 and 64 a year on average in 2008-2025; in 2021-2025 it had the 14th most of any state. 2026 through September: 70, 56% above the average of 45 for those months in 2008-2025. Douglas was covered most often (238 times since 2008).
How many dense fog advisories does Wisconsin get?
Every dense fog advisory that covered part of Wisconsin. 2026 is an outline: the year is not over.
The numbers
| Year | Count |
|---|---|
| 2026 (through September) | 70 |
| 2025 | 89 |
| 2024 | 89 |
| 2023 | 63 |
| 2022 | 64 |
| 2021 | 67 |
| 2020 | 43 |
| 2019 | 77 |
| 2018 | 64 |
| 2017 | 65 |
| 2016 | 40 |
| 2015 | 44 |
| 2014 | 74 |
| 2013 | 87 |
| 2012 | 71 |
| 2011 | 49 |
| 2010 | 70 |
| 2009 | 51 |
| 2008 | 52 |
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
When in the year does Wisconsin get them?
Sum of 2008-2025; the busiest month is labelled.
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
Where in Wisconsin?
| County or forecast zone | Since 2008 | Since 2023 | Last issued |
|---|---|---|---|
| Douglas | 238 | 78 | September 28, 2026 |
| Sheboygan | 232 | 39 | June 10, 2026 |
| Washington | 227 | 46 | August 13, 2026 |
| Waukesha | 222 | 44 | August 13, 2026 |
| Walworth | 220 | 48 | September 30, 2026 |
| Ozaukee | 218 | 34 | June 10, 2026 |
| Green | 214 | 44 | August 13, 2026 |
| Rock | 213 | 48 | August 13, 2026 |
| Kenosha | 212 | 37 | September 30, 2026 |
| Racine | 210 | 36 | September 30, 2026 |
| Milwaukee | 200 | 33 | July 27, 2026 |
| Jefferson | 199 | 41 | August 13, 2026 |
The NWS issues these products for counties or forecast zones; a zone can be part of a county or a mountain range.
Source: Iowa Environmental Mesonet archive of National Weather Service watches, warnings and advisories (VTEC); National Weather Service. Data as of October 1, 2026.
What is a dense fog advisory?
A dense fog advisory means fog will cut visibility to a quarter mile or less over a wide area. An advisory is issued for a hazard less serious than a warning that can still cause inconvenience or danger if people are not careful. The national record · Every warning type in Wisconsin.