Dense Fog Advisories in Illinois, 2017

Dense Fog Advisories by county

Each county as a circle sized by its count in 2017. 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 1, 8:43 PM CST	Dense Fog Advisory	ILX	Clay, Lawrence, Richland	7 hr
Jan 1, 8:54 PM CST	Dense Fog Advisory	LSX	Clinton, Marion, Monroe, Randolph, Saint Clair, Washington	12 hr
Jan 1, 9:36 PM CST	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	11 hr
Jan 2, 4:31 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	15 hr
Jan 2, 4:59 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	15 hr
Jan 2, 5:07 PM CST	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	15 hr
Jan 2, 5:43 PM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	13 hr
Jan 2, 6:30 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	17 hr
Jan 10, 10:10 PM CST	Dense Fog Advisory	PAH	Alexander, Hardin, Jackson, Johnson, Massac, Pope and 4 more	5 hr
Jan 11, 11:53 AM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 27 more	9 hr
Jan 11, 1:15 PM CST	Dense Fog Advisory	LOT	DeKalb, DuPage, Ford, Grundy, Iroquois, Kane and 6 more	7 hr
Jan 11, 1:32 PM CST	Dense Fog Advisory	DVN	Bureau, Henry, Mercer, Putnam, Warren, Whiteside	6 hr
Jan 13, 11:15 PM CST	Dense Fog Advisory	PAH	Alexander, Gallatin, Hardin, Johnson, Massac, Pope and 4 more	12 hr
Jan 15, 10:41 PM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	13 hr
Jan 15, 10:42 PM CST	Dense Fog Advisory	PAH	Alexander, Franklin, Gallatin, Hamilton, Hardin, Jackson and 9 more	11 hr
Jan 15, 10:45 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	13 hr
Jan 16, 12:04 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Coles, Cumberland, DeWitt and 23 more	17 hr
Jan 16, 12:13 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	17 hr
Jan 16, 3:33 PM CST	Dense Fog Advisory	LSX	Adams, Brown, Pike	7 hr
Jan 16, 4:30 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	14 hr
Jan 19, 3:08 PM CST	Dense Fog Advisory	ILX	Cass, Christian, DeWitt, Fulton, Knox, Logan and 16 more	19 hr
Jan 19, 3:26 PM CST	Dense Fog Advisory	DVN	Hancock, Henderson, Henry, McDonough, Mercer, Rock Island and 1 more	21 hr
Jan 19, 3:35 PM CST	Dense Fog Advisory	PAH	Alexander, Franklin, Jackson, Jefferson, Johnson, Perry and 3 more	14 hr
Jan 19, 3:37 PM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	20 hr
Jan 20, 3:14 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	21 hr
Jan 20, 4:29 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Grundy, Kane, Kendall and 6 more	19 hr
Jan 21, 3:50 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	19 hr
Jan 21, 9:08 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	15 hr
Jan 22, 1:41 AM CST	Dense Fog Advisory	ILX	Cass, DeWitt, Fulton, Knox, Logan, McLean and 11 more	9 hr
Feb 6, 4:56 PM CST	Dense Fog Advisory	ILX	Champaign, Clark, Coles, DeWitt, Douglas, Edgar and 14 more	13 hr
Feb 6, 7:07 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	19 hr
Feb 6, 9:10 PM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	15 hr
Feb 19, 1:00 AM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 22 more	10 hr
Feb 19, 1:14 AM CST	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	10 hr
Feb 19, 1:24 AM CST	Dense Fog Advisory	LSX	Bond, Clinton, Fayette, Jersey, Macoupin, Madison and 6 more	10 hr
Feb 19, 6:09 AM CST	Dense Fog Advisory	LOT	Ford, Iroquois, Livingston	6 hr
Feb 19, 9:18 PM CST	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more	9 hr
Feb 19, 10:08 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	11 hr
Feb 19, 10:15 PM CST	Dense Fog Advisory	LSX	Bond, Clinton, Fayette, Greene, Jersey, Macoupin and 7 more	8 hr
Feb 20, 3:41 AM CST	Dense Fog Advisory	LOT	Ford, Grundy, Iroquois, Kankakee, Kendall, LaSalle and 1 more	6 hr
Feb 21, 10:42 PM CST	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Fayette and 11 more	10 hr
Feb 21, 10:51 PM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	12 hr
Feb 21, 11:34 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	11 hr
Feb 22, 12:26 AM CST	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	10 hr
Feb 22, 7:01 AM CST	Dense Fog Advisory	PAH	Edwards, Franklin, Gallatin, Hamilton, Jefferson, Perry and 5 more	3 hr
Feb 23, 4:25 AM CST	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 22 more	6 hr
Feb 23, 5:52 AM CST	Dense Fog Advisory	LSX	Calhoun, Fayette, Greene, Jersey, Macoupin, Marion and 2 more	3 hr
Feb 23, 7:02 AM CST	Dense Fog Advisory	LOT	Ford, Iroquois, Kankakee	3 hr
Mar 17, 10:10 PM CDT	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 12 more	9 hr
Mar 26, 5:22 AM CDT	Dense Fog Advisory	DVN	Carroll, Jo Daviess, Rock Island, Stephenson, Whiteside	7 hr
Mar 26, 5:26 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, Lee, Ogle, Winnebago	5 hr
Mar 28, 7:17 PM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Kane, Lake, Lee and 3 more	14 hr
Apr 11, 3:42 AM CDT	Dense Fog Advisory	LOT	DuPage, Grundy, Kane, Kendall	3 hr
Apr 19, 5:03 AM CDT	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Hamilton, Jackson, Jefferson and 9 more	3 hr
May 21, 12:25 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Kane, Lake, Lee and 3 more	5 hr
May 27, 1:53 AM CDT	Dense Fog Advisory	DVN	Carroll, Hancock, Henderson, Henry, Jo Daviess, McDonough and 5 more	8 hr
Jun 5, 5:24 AM CDT	Dense Fog Advisory	LSX	Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 6 more	4 hr
Jun 5, 6:14 AM CDT	Dense Fog Advisory	ILX	Christian, Clay, Effingham, Jasper, Richland, Shelby	96 min
Aug 15, 4:04 AM CDT	Dense Fog Advisory	PAH	Alexander, Jackson, Johnson, Massac, Pulaski, Union	5 hr
Aug 28, 2:18 AM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	9 hr
Aug 28, 2:34 AM CDT	Dense Fog Advisory	ILX	Cass, Fulton, Knox, Marshall, Mason, Menard and 7 more	6 hr
Aug 28, 3:47 AM CDT	Dense Fog Advisory	LSX	Adams, Brown, Calhoun, Greene, Jersey, Macoupin and 1 more	7 hr
Aug 28, 11:07 PM CDT	Dense Fog Advisory	ILX	Cass, Christian, DeWitt, Fulton, Knox, Logan and 14 more	11 hr
Aug 29, 2:02 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 9 more	7 hr
Aug 29, 2:41 AM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	8 hr
Aug 29, 4:15 AM CDT	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Clinton, Greene and 9 more	6 hr
Aug 30, 4:30 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 9 more	5 hr
Aug 30, 4:37 AM CDT	Dense Fog Advisory	ILX	Cass, Champaign, Christian, DeWitt, Douglas, Fulton and 18 more	4 hr
Aug 30, 4:52 AM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Hancock, Henderson, Henry, Jo Daviess and 7 more	4 hr
Sep 14, 1:09 AM CDT	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Clark, Clay, Coles and 29 more	9 hr
Sep 14, 1:14 AM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	9 hr
Sep 14, 3:19 AM CDT	Dense Fog Advisory	LSX	Bond, Brown, Calhoun, Clinton, Fayette, Greene and 10 more	6 hr
Sep 14, 4:28 AM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Henry, McDonough, Putnam, Stephenson and 2 more	6 hr
Sep 14, 6:10 AM CDT	Dense Fog Advisory	PAH	Alexander, Edwards, Franklin, Hamilton, Jackson, Jefferson and 9 more	3 hr
Sep 15, 5:01 AM CDT	Dense Fog Advisory	PAH	Edwards, Gallatin, Hamilton, Hardin, Saline, Wabash and 2 more	4 hr
Sep 18, 11:19 PM CDT	Dense Fog Advisory	LSX	Adams, Bond, Brown, Calhoun, Greene, Jersey and 6 more	11 hr
Sep 19, 12:50 AM CDT	Dense Fog Advisory	DVN	Hancock, Henderson, McDonough, Mercer, Rock Island, Warren	9 hr
Sep 19, 1:18 AM CDT	Dense Fog Advisory	ILX	Cass, Christian, DeWitt, Fulton, Knox, Logan and 9 more	9 hr
Sep 20, 12:31 AM CDT	Dense Fog Advisory	LOT	Lake, McHenry	8 hr
Oct 8, 5:20 AM CDT	Dense Fog Advisory	ILX	Clark, Clay, Coles, Crawford, Cumberland, Edgar and 5 more	4 hr
Oct 8, 5:23 AM CDT	Dense Fog Advisory	LSX	Bond, Calhoun, Clinton, Fayette, Greene, Jersey and 7 more	4 hr
Oct 9, 4:13 AM CDT	Dense Fog Advisory	PAH	Alexander, Franklin, Jackson, Jefferson, Johnson, Massac and 4 more	5 hr
Oct 9, 5:22 AM CDT	Dense Fog Advisory	LSX	Bond, Clinton, Fayette, Jersey, Macoupin, Madison and 6 more	6 hr
Oct 9, 7:47 AM CDT	Dense Fog Advisory	ILX	Cass, Champaign, Christian, Coles, DeWitt, Douglas and 15 more	3 hr
Nov 2, 1:31 AM CDT	Dense Fog Advisory	DVN	Bureau, Henderson, Henry, Mercer, Putnam, Rock Island and 2 more	9 hr
Nov 2, 1:36 AM CDT	Dense Fog Advisory	ILX	Knox, Marshall, Stark	8 hr
Nov 4, 5:39 AM CDT	Dense Fog Advisory	PAH	Alexander, Massac, Pulaski	3 hr
Nov 4, 11:19 PM CDT	Dense Fog Advisory	DVN	Bureau, Carroll, Henderson, Henry, Jo Daviess, Mercer and 5 more	8 hr
Nov 4, 11:33 PM CDT	Dense Fog Advisory	LOT	Boone, DeKalb, DuPage, Ford, Grundy, Iroquois and 10 more	10 hr
Nov 5, 3:58 AM CST	Dense Fog Advisory	ILX	Cass, Champaign, DeWitt, Fulton, Knox, Logan and 15 more	6 hr
Nov 12, 9:39 PM CST	Dense Fog Advisory	DVN	Carroll, Jo Daviess, Rock Island, Stephenson, Whiteside	14 hr
Nov 12, 9:39 PM CST	Dense Fog Advisory	LOT	Boone, DeKalb, Kane, Lee, McHenry, Ogle and 1 more	14 hr
Dec 19, 6:49 PM CST	Dense Fog Advisory	PAH	Alexander, Massac, Pulaski	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 2016 2018

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.