Dense Fog Advisories in Illinois, 2018

Dense Fog Advisories by county

Each county as a circle sized by its count in 2018. 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
Jan 7, 9:42 PM CST	Dense Fog Advisory	LSX	Adams, Brown, Pike	10 hr
Jan 8, 3:36 PM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	20 hr
Jan 8, 9:31 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	14 hr
Jan 8, 9:53 PM CST	Dense Fog Advisory	LOT	DeKalb, DuPage, Ford, Grundy, Iroquois, Kane and 4 more	14 hr
Jan 8, 10:03 PM CST	Dense Fog Advisory	DVN	Bureau, Hancock, Henderson, Henry, McDonough, Mercer and 2 more	12 hr
Jan 9, 2:19 AM CST	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	8 hr
Jan 9, 3:28 PM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	18 hr
Jan 9, 6:38 PM CST	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	17 hr
Jan 9, 7:17 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	17 hr
Jan 9, 11:32 PM CST	Dense Fog Advisory	DVN	Hancock, Henderson, McDonough, Warren	7 hr
Jan 10, 3:32 AM CST	Dense Fog Advisory	LOT	Boone, McHenry, Winnebago	4 hr
Jan 10, 8:56 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	10 hr
Jan 10, 2:57 PM CST	Dense Fog Advisory	DVN	Carroll, Jo Daviess, Stephenson	8 hr
Jan 21, 2:25 AM CST	Dense Fog Advisory	ILX	Champaign, Clark, Clay, Coles, Cumberland, DeWitt and 15 more	14 hr
Jan 21, 3:52 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	26 hr
Jan 21, 4:01 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Henry, Jo Daviess, Putnam, Rock Island and 2 more	14 hr
Jan 27, 9:23 PM CST	Dense Fog Advisory	PAH	Gallatin, Hardin, Massac, Pope	8 hr
Feb 14, 5:14 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	25 hr
Feb 14, 5:42 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	20 hr
Feb 14, 7:45 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, DeWitt, Fulton, Knox, Logan and 15 more	22 hr
Feb 17, 10:05 PM CST	Dense Fog Advisory	PAH	Alexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 11 more	11 hr
Feb 18, 2:28 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Henry, Jo Daviess, Mercer, Putnam and 3 more	8 hr
Feb 18, 3:36 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	6 hr
Feb 18, 6:17 AM CST	Dense Fog Advisory	LSX	Randolph	3 hr
Feb 19, 1:39 PM CST	Dense Fog Advisory	DVN	Carroll, Jo Daviess, Stephenson	13 hr
Feb 19, 8:24 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, Kane, Lake, Lee, McHenry and 2 more	5 hr
Feb 22, 8:58 PM CST	Dense Fog Advisory	LSX	Adams, Brown, Pike	7 hr
Feb 28, 11:05 PM CST	Dense Fog Advisory	ILX	Champaign, Christian, Clark, Coles, Cumberland, Douglas and 11 more	5 hr
Feb 28, 11:10 PM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Fayette, Greene and 5 more	5 hr
Mar 18, 2:16 AM CDT	Dense Fog Advisory	ILX	Cass, Christian, DeWitt, Fulton, Knox, Logan and 13 more	8 hr
Mar 18, 2:25 AM CDT	Dense Fog Advisory	DVN	Hancock, Henderson, McDonough, Mercer, Rock Island, Warren	9 hr
Apr 2, 2:11 AM CDT	Dense Fog Advisory	ILX	Cass, Champaign, DeWitt, Fulton, Logan, McLean and 12 more	7 hr
Apr 2, 2:11 AM CDT	Dense Fog Advisory	LSX	Adams, Brown, Pike	7 hr
Apr 2, 2:24 AM CDT	Dense Fog Advisory	DVN	Hancock, McDonough	8 hr
May 19, 3:41 AM CDT	Dense Fog Advisory	LSX	Adams, Pike	5 hr
May 19, 9:01 AM CDT	Dense Fog Advisory	LSX	Adams, Pike	99 min
May 21, 9:52 PM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Grundy, Kane, Kankakee and 8 more	12 hr
May 22, 3:34 AM CDT	Dense Fog Advisory	DVN	Carroll, Jo Daviess, Stephenson	5 hr
May 22, 6:24 AM CDT	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Jackson and 12 more	3 hr
Jun 2, 4:48 AM CDT	Dense Fog Advisory	PAH	Alexander	4 hr
Jun 9, 5:23 PM CDT	Dense Fog Advisory	LOT	Lake	10 hr
Jul 17, 3:59 AM CDT	Dense Fog Advisory	LOT	Iroquois	3 hr
Jul 27, 1:19 AM CDT	Dense Fog Advisory	LSX	Clinton, Marion, Monroe, Randolph, Saint Clair, Washington	7 hr
Jul 27, 5:07 AM CDT	Dense Fog Advisory	PAH	Edwards, Franklin, Gallatin, Hamilton, Jackson, Jefferson and 6 more	3 hr
Aug 1, 3:34 AM CDT	Dense Fog Advisory	ILX	Christian, Clark, Clay, Coles, Crawford, Cumberland and 11 more	5 hr
Aug 1, 6:39 AM CDT	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 11 more	2 hr
Aug 3, 5:40 AM CDT	Dense Fog Advisory	LOT	Boone, McHenry, Winnebago	2 hr
Aug 8, 4:07 AM CDT	Dense Fog Advisory	DVN	Henry, Rock Island	5 hr
Aug 10, 3:10 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Kane, Lee, McHenry and 2 more	6 hr
Aug 16, 3:00 AM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	6 hr
Aug 16, 3:17 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, LaSalle, Lee, Ogle, Winnebago	6 hr
Aug 16, 3:20 AM CDT	Dense Fog Advisory	ILX	Cass, Fulton, Knox, Marshall, Mason, Menard and 5 more	6 hr
Aug 17, 6:41 AM CDT	Dense Fog Advisory	DVN	Rock Island	2 hr
Aug 19, 4:21 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, Ford, Grundy, Iroquois, Kane and 8 more	5 hr
Aug 25, 4:03 AM CDT	Dense Fog Advisory	DVN	Jo Daviess	6 hr
Aug 26, 3:03 AM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Jo Daviess, Putnam, Stephenson, Whiteside	5 hr
Aug 26, 3:07 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Grundy, Kane, Kendall and 6 more	6 hr
Sep 11, 2:43 AM CDT	Dense Fog Advisory	ILX	Clark, Clay, Coles, Crawford, Cumberland, Edgar and 5 more	6 hr
Sep 11, 4:36 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Grundy, Kane, Kankakee and 6 more	4 hr
Sep 28, 2:31 AM CDT	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 11 more	7 hr
Sep 28, 2:35 AM CDT	Dense Fog Advisory	ILX	Clark, Clay, Crawford, Jasper, Lawrence, Richland	6 hr
Oct 7, 5:33 AM CDT	Dense Fog Advisory	LSX	Madison, Monroe, Saint Clair	3 hr
Oct 13, 6:52 AM CDT	Dense Fog Advisory	DVN	Henry, Rock Island, Whiteside	2 hr
Nov 2, 7:04 AM CDT	Dense Fog Advisory	LSX	Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 6 more	3 hr
Nov 3, 3:03 AM CDT	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	6 hr
Nov 3, 3:39 AM CDT	Dense Fog Advisory	ILX	Cass, Christian, Clay, Cumberland, Effingham, Fulton and 13 more	6 hr
Nov 29, 9:55 PM CST	Dense Fog Advisory	LSX	Randolph	14 hr
Nov 29, 10:11 PM CST	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	12 hr
Nov 30, 3:35 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, Kane, LaSalle, Lee, McHenry and 2 more	6 hr
Nov 30, 3:37 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	6 hr
Nov 30, 6:27 AM CST	Dense Fog Advisory	ILX	Fulton, Knox, Marshall, Peoria, Stark	3 hr
Nov 30, 9:22 AM CST	Dense Fog Advisory	ILX	Clark, Clay, Crawford, Edgar, Effingham, Jasper and 2 more	3 hr
Nov 30, 8:09 PM CST	Dense Fog Advisory	ILX	Champaign, DeWitt, McLean, Piatt, Vermilion, Woodford	8 hr
Nov 30, 8:09 PM CST	Dense Fog Advisory	LOT	Ford, Iroquois, Livingston	10 hr
Dec 1, 12:36 PM CST	Dense Fog Advisory	DVN	Bureau, Hancock, Henderson, Henry, McDonough, Mercer and 4 more	20 hr
Dec 1, 12:39 PM CST	Dense Fog Advisory	ILX	Fulton, Knox, Stark	4 hr
Dec 2, 3:27 AM CST	Dense Fog Advisory	LOT	DeKalb, DuPage, Kane, Lake, Lee, McHenry and 1 more	4 hr
Dec 9, 9:45 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	16 hr
Dec 10, 12:42 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	9 hr
Dec 10, 3:12 AM CST	Dense Fog Advisory	ILX	Champaign, Christian, Clark, Clay, Coles, Crawford and 20 more	11 hr
Dec 10, 5:22 PM CST	Dense Fog Advisory	ILX	Champaign, Coles, Douglas, Edgar, Moultrie, Piatt and 1 more	6 hr
Dec 10, 6:39 PM CST	Dense Fog Advisory	LOT	Ford, Iroquois	5 hr
Dec 13, 9:42 AM CST	Dense Fog Advisory	DVN	Bureau, Henderson, Henry, Mercer, Putnam, Warren	3 hr
Dec 13, 3:06 PM CST	Dense Fog Advisory	ILX	Champaign, DeWitt, Fulton, Knox, Logan, McLean and 9 more	5 hr
Dec 13, 4:56 PM CST	Dense Fog Advisory	DVN	Bureau, Hancock, Henderson, Henry, McDonough, Mercer and 3 more	3 hr
Dec 13, 11:58 PM CST	Dense Fog Advisory	DVN	Carroll, Hancock, Henderson, Henry, Jo Daviess, McDonough and 5 more	9 hr
Dec 14, 1:43 PM CST	Dense Fog Advisory	ILX	Cass, DeWitt, Fulton, Knox, Logan, McLean and 11 more	13 hr
Dec 14, 3:57 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, McDonough and 6 more	11 hr
Dec 14, 4:10 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	18 hr
Dec 14, 4:59 PM CST	Dense Fog Advisory	LSX	Adams, Brown, Pike	6 hr
Dec 16, 12:54 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 5 more	9 hr
Dec 20, 9:34 AM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Kane, Lake, LaSalle and 4 more	8 hr

By county

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

60 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 2017 2019

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.