Dense Fog Advisories in Illinois, 2023

Dense Fog Advisories by county

Each county as a circle sized by its count in 2023. Tap one for its archive.

Over time

By month

The alerts

Every alert, in the order issued. Times are local, Central Time. Each opens its own page with the text, the map, the radar and the sounding.

Issued	Product	Office	Counties	Lasted
Dec 31, 9:53 PM CST	Dense Fog Advisory	PAH	Alexander, Gallatin, Hamilton, Hardin, Johnson, Massac and 6 more	10 hr
Jan 1, 5:52 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	5 hr
Jan 1, 5:52 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, Grundy, Kane, Kendall, LaSalle and 4 more	6 hr
Jan 1, 8:50 AM CST	Dense Fog Advisory	ILX	Fulton, Knox, McLean, Marshall, Peoria, Stark and 2 more	2 hr
Jan 1, 5:13 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, McDonough and 6 more	25 hr
Jan 1, 5:16 PM CST	Dense Fog Advisory	LOT	Boone, Cook, DeKalb, DuPage, Ford, Grundy and 11 more	16 hr
Jan 1, 7:13 PM CST	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	9 hr
Jan 1, 11:43 PM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	15 hr
Jan 1, 11:46 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	15 hr
Jan 2, 9:04 AM CST	Dense Fog Advisory	LOT	Cook, DuPage, Ford, Grundy, Iroquois, Kankakee and 2 more	19 hr
Jan 2, 3:33 PM CST	Dense Fog Advisory	ILX	Champaign, DeWitt, McLean, Piatt, Vermilion	8 hr
Jan 3, 5:14 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	17 hr
Jan 3, 5:37 AM CST	Dense Fog Advisory	ILX	Fulton, Knox, McLean, Marshall, Peoria, Stark and 2 more	7 hr
Jan 3, 9:35 AM CST	Dense Fog Advisory	LOT	Boone, Cook, DeKalb, DuPage, Grundy, Kane and 10 more	16 hr
Jan 8, 4:34 AM CST	Dense Fog Advisory	DVN	Jo Daviess	7 hr
Jan 11, 9:30 PM CST	Dense Fog Advisory	ILX	Champaign, Christian, Clark, Clay, Coles, Crawford and 15 more	6 hr
Jan 17, 4:34 AM CST	Dense Fog Advisory	PAH	Alexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 8 more	4 hr
Jan 19, 4:44 AM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Coles, Cumberland and 23 more	4 hr
Jan 19, 7:44 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	3 hr
Jan 19, 8:26 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, Ford, Grundy, Iroquois, Kankakee and 5 more	2 hr
Feb 23, 4:19 AM CST	Dense Fog Advisory	LOT	Cook, DeKalb, DuPage, Ford, Grundy, Iroquois and 6 more	5 hr
Mar 4, 10:24 PM CST	Dense Fog Advisory	LOT	Boone, Cook, DeKalb, DuPage, Ford, Grundy and 11 more	11 hr
Mar 4, 10:26 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	9 hr
Mar 5, 12:22 AM CST	Dense Fog Advisory	ILX	Champaign, Fulton, Knox, McLean, Marshall, Peoria and 4 more	8 hr
Mar 26, 9:52 PM CDT	Dense Fog Advisory	DVN	Jo Daviess	7 hr
May 13, 1:51 AM CDT	Dense Fog Advisory	PAH	Edwards, Franklin, Gallatin, Hamilton, Jefferson, Saline and 3 more	6 hr
May 13, 6:52 AM CDT	Dense Fog Advisory	ILX	Champaign, DeWitt, Fulton, Knox, Logan, McLean and 7 more	2 hr
Jun 8, 4:36 AM CDT	Dense Fog Advisory	PAH	Alexander, Hardin, Johnson, Massac, Pope, Pulaski	3 hr
Jun 30, 3:39 AM CDT	Dense Fog Advisory	ILX	Cass, Champaign, Christian, DeWitt, Fulton, Knox and 16 more	5 hr
Jun 30, 3:45 AM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, McDonough and 6 more	4 hr
Jun 30, 4:27 AM CDT	Dense Fog Advisory	LOT	DeKalb, DuPage, Ford, Grundy, Iroquois, Kane and 7 more	5 hr
Jul 27, 4:06 AM CDT	Dense Fog Advisory	LOT	Cook, Ford, Grundy, Iroquois, Kankakee, Kendall and 2 more	4 hr
Aug 2, 9:41 PM CDT	Dense Fog Advisory	DVN	Carroll, Henry, Jo Daviess, Mercer, Rock Island, Stephenson and 1 more	11 hr
Aug 3, 4:18 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, Kane, Lee, McHenry, Ogle and 1 more	5 hr
Aug 4, 1:18 AM CDT	Dense Fog Advisory	PAH	Edwards, Gallatin, Wabash, White	4 hr
Aug 4, 2:50 AM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Henry, Mercer, Putnam, Rock Island and 1 more	6 hr
Aug 4, 5:17 AM CDT	Dense Fog Advisory	LOT	DeKalb, Ford, Grundy, Iroquois, Kankakee, Kendall and 5 more	3 hr
Aug 4, 5:19 AM CDT	Dense Fog Advisory	ILX	McLean, Marshall, Peoria, Stark, Tazewell, Woodford	4 hr
Aug 9, 3:46 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, Grundy, Kane, Kendall, LaSalle and 4 more	4 hr
Aug 9, 4:19 AM CDT	Dense Fog Advisory	DVN	Bureau, Putnam, Whiteside	4 hr
Aug 9, 11:23 PM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	10 hr
Aug 10, 1:04 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, Grundy, Kane, Kankakee, Kendall and 6 more	8 hr
Aug 10, 1:05 AM CDT	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	8 hr
Aug 10, 1:11 AM CDT	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	8 hr
Aug 10, 9:19 PM CDT	Dense Fog Advisory	PAH	Alexander, Gallatin, Hardin, Johnson, Massac, Pope and 4 more	11 hr
Aug 22, 2:38 AM CDT	Dense Fog Advisory	ILX	Clark, Clay, Crawford, Cumberland, Effingham, Jasper and 2 more	5 hr
Aug 22, 3:26 AM CDT	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	5 hr
Aug 22, 3:27 AM CDT	Dense Fog Advisory	LSX	Clinton, Marion, Monroe, Randolph, Saint Clair, Washington	5 hr
Aug 23, 1:44 AM CDT	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	6 hr
Aug 23, 4:50 AM CDT	Dense Fog Advisory	LSX	Clinton, Marion, Monroe, Randolph, Saint Clair, Washington	3 hr
Sep 12, 2:05 AM CDT	Dense Fog Advisory	DVN	Hancock, Henderson, McDonough, Warren	6 hr
Sep 12, 2:26 AM CDT	Dense Fog Advisory	ILX	Cass, Fulton, Knox, Marshall, Mason, Peoria and 4 more	6 hr
Sep 12, 2:31 AM CDT	Dense Fog Advisory	LSX	Adams, Brown	6 hr
Sep 25, 9:07 AM CDT	Dense Fog Advisory	DVN	Henry, Mercer, Rock Island	2 hr
Sep 28, 3:21 AM CDT	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 22 more	6 hr
Sep 28, 3:59 AM CDT	Dense Fog Advisory	DVN	Hancock, Henderson, McDonough, Warren	6 hr
Sep 28, 10:44 PM CDT	Dense Fog Advisory	ILX	Champaign, Clark, Coles, DeWitt, Douglas, Edgar and 7 more	10 hr
Sep 29, 1:23 AM CDT	Dense Fog Advisory	DVN	Bureau, Putnam, Stephenson	8 hr
Sep 29, 1:34 AM CDT	Dense Fog Advisory	LOT	Boone, Cook, DeKalb, DuPage, Ford, Grundy and 11 more	7 hr
Sep 30, 1:58 AM CDT	Dense Fog Advisory	PAH	Massac, Pope	7 hr
Oct 5, 9:00 PM CDT	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	10 hr
Nov 5, 12:33 AM CDT	Dense Fog Advisory	LOT	Cook, DuPage, Ford, Grundy, Iroquois, Kankakee and 2 more	10 hr
Nov 5, 12:46 AM CDT	Dense Fog Advisory	ILX	Champaign, Edgar, Vermilion	10 hr
Nov 7, 5:50 AM CST	Dense Fog Advisory	ILX	Christian, Clark, Clay, Coles, Crawford, Cumberland and 8 more	12 min
Nov 7, 6:02 AM CST	Dense Fog Advisory	ILX	Christian, Clark, Clay, Coles, Crawford, Cumberland and 8 more	116 min
Dec 1, 9:49 PM CST	Dense Fog Advisory	PAH	Gallatin, Hardin, Massac, Pope	9 hr
Dec 22, 6:23 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	18 hr
Dec 22, 6:28 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, DeWitt, Fulton, Knox, Logan and 12 more	19 hr
Dec 22, 8:40 PM CST	Dense Fog Advisory	LSX	Adams, Brown	12 hr
Dec 22, 11:35 PM CST	Dense Fog Advisory	LOT	Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more	12 hr
Dec 23, 3:29 PM CST	Dense Fog Advisory	LOT	Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more	21 hr
Dec 23, 4:15 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	20 hr
Dec 23, 6:31 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Coles, DeWitt, Douglas and 21 more	17 hr
Dec 24, 1:19 AM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Greene, Jersey and 5 more	8 hr
Dec 30, 2:02 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Henry, Jo Daviess, Putnam, Rock Island and 2 more	8 hr
Dec 30, 6:56 AM CST	Dense Fog Advisory	LOT	Boone, Cook, DeKalb, DuPage, Grundy, Kane and 9 more	5 hr
Dec 30, 7:01 AM CST	Dense Fog Advisory	ILX	McLean, Marshall, Peoria, Stark, Tazewell, Woodford	4 hr

By county

Every county with at least one alert. A county page lists each alert that covered it.

62 more counties

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force now Tornadoes on record The radar archive 2022 2024

Sources

National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.