National Weather ServiceConnecticutDense Fog AdvisoryArchive to October 1, 2026
Dense Fog Advisories in Connecticut
The National Weather Service issued 6 dense fog advisories for Connecticut in 2025 and 16 a year on average in 2008-2025; in 2021-2025 it had the 42nd most of any state. 2026 through September: 4, 65% below the average of 11 for those months in 2008-2025. Southern New London was covered most often (178 times since 2008).
How many dense fog advisories does Connecticut get?
Every dense fog advisory that covered part of Connecticut. 2026 is an outline: the year is not over.
The numbers
| Year | Count |
|---|---|
| 2026 (through September) | 4 |
| 2025 | 6 |
| 2024 | 10 |
| 2023 | 20 |
| 2022 | 20 |
| 2021 | 9 |
| 2020 | 21 |
| 2019 | 14 |
| 2018 | 25 |
| 2017 | 19 |
| 2016 | 6 |
| 2015 | 36 |
| 2014 | 13 |
| 2013 | 25 |
| 2012 | 16 |
| 2011 | 24 |
| 2010 | 5 |
| 2009 | 13 |
| 2008 | 12 |
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 Connecticut 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 Connecticut?
| County or forecast zone | Since 2008 | Since 2023 | Last issued |
|---|---|---|---|
| Southern New London | 178 | 23 | March 16, 2026 |
| Southern Middlesex | 174 | 23 | March 16, 2026 |
| Southern New Haven | 163 | 22 | March 16, 2026 |
| Southern Fairfield | 140 | 18 | March 16, 2026 |
| Northern New London | 111 | 16 | March 16, 2026 |
| Northern Middlesex | 106 | 16 | March 16, 2026 |
| Northern New Haven | 106 | 16 | March 16, 2026 |
| Northern Fairfield | 87 | 13 | March 16, 2026 |
| Windham | 78 | 12 | March 31, 2025 |
| Hartford | 65 | 10 | March 31, 2025 |
| Tolland | 65 | 10 | March 31, 2025 |
| Northern Litchfield | 20 | 3 | December 29, 2024 |
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 Connecticut.