Dense Fog in Illinois

Events

2,188

Deaths

10

Injuries

54

Damage

$219,000

• Dense Fog in Illinois, February 4, 20082 deaths · 6 injured · 3 eventsDense fog formed across northern Illinois during the morning hours of February 4th and continued into the afternoon. Numerous car accidents were reported with injuries and fatalities.
• Dense Fog in Illinois, March 9 to 11, 20152 deaths · 4 injured · 1 eventDense fog developed across north central Illinois the morning of the 10th and continued through the day at some locations.
• Dense Fog in Illinois, February 4, 20081 death · 21 injured · 3 eventsA warm front was slowly moving to the north across Missouri and Illinois. Dense fog formed north of the front reducing visibilities to near zero in many locations. Several major accidents were reported.
• Dense Fog in Illinois, February 22, 20171 death · 10 injured · 1 eventAn unseasonably warm and humid airmass flowing northward over cold ground produced widespread dense fog during the morning of February 22nd. Visibilities were frequently reduced to less than one quarter of a mile, prompting the issuance of a Dense Fog Advisory.
• Dense Fog in Illinois, February 4 to 5, 20081 death · 35 eventsA period of rain and mild temperatures over melting snow pack cause an extended period of dense fog across much of central and southeast Illinois. Numerous school closures and vehicular accidents occurred as a result of the dense fog.
• Dense Fog in Illinois, August 26, 20251 death · $19,000 · 1 eventVery isolated dense fog developed near Fountain in Monroe County during the early morning of August 26th. At around 6:20 AM CDT, deputies were called to the seen of an overturned vehicle with an individual thrown out of it. The person was pronounced dead at the scene.
• Dense Fog in Illinois, December 7, 20151 death · 1 injured · 1 eventAfter a period of scattered light showers the day before, skies gradually cleared and winds became nearly calm during the pre-dawn hours of December 7th. As a result, widespread dense fog developed across central Illinois, particularly north of the I-70 corridor.
• Dense Fog in Illinois, September 25 to 26, 20091 death · 1 eventA weak area of high pressure, a clear sky and a saturated ground from recent rainfall resulted in widespread dense fog across all of central and southeast Illinois. In Logan County, a man died in a traffic accident attributed to the dense fog.
• Dense Fog in Illinois, February 20, 201412 injured · $100,000 · 1 eventDense fog developed during the afternoon of February 20th. A 20-car pileup occurred on Interstate 57 near Peotone along with clusters of accidents along a stretch of the interstate.
• Dense Fog in Illinois, June 1, 2010$100,000 · 1 eventDense fog developed across parts of northwest Illinois during the early morning hours of June 1st. A 13 vehicle accident occurred on Route 64 north of Rochelle due to the low visibility. A semi truck and garbage truck were involved in the accident.
• Dense Fog in Illinois, September 25 to 26, 200920 eventsDense fog formed as a result of calm winds and moist air under a high pressure system. Rain during the previous 24 hours moistened the ground, contributing to high humidity. Visibility was below a quarter mile for most of the night into early the next morning.
• Dense Fog in Illinois, December 18, 199719 eventsPatchy dense fog reduced visibility to near zero in some spots. With temperatures in the mid 20s, a layer of frost formed, even on some roads. This resulted in slick spots for early morning commuters.
• Dense Fog in Illinois, December 9, 199719 eventsWidespread dense fog caused hazardous travel conditions. Visibility was generally a quarter mile or less over the area.
• Dense Fog in Illinois, January 30, 199819 eventsWidespread dense fog caused travel difficulties during the early morning hours. Illinois State Police reported visibility as low as two car lengths near Metropolis in Massac County.
• Dense Fog in Illinois, January 27, 199819 eventsWidespread dense fog developed over far southern Illinois during the early morning hours. The most persistent dense fog occurred in the Marion/Carbondale area, where visibility was locally near zero for several hours. The dense fog hindered early morning commuters.
• Dense Fog in Illinois, January 6, 199819 eventsDense fog reduced visibility to a quarter mile or less across much of the area.
• Dense Fog in Illinois, October 15 to 16, 200019 eventsWidespread dense fog blanketed all of southern Illinois from late evening on the 15th until the mid morning hours on the 16th. State police reported a rollover vehicle accident in the Mount Vernon area was due to the fog.
• Dense Fog in Illinois, March 31, 200119 eventsWidespread dense fog formed around midnight. During the early morning hours, visibility was below a quarter mile. One fatal accident was attributed to the fog. An elderly man driving east on Illinois 146 in Hardin County failed to stop where the road ends at Illinois Route 1.
• Dense Fog in Illinois, August 8, 200519 eventsDense fog blanketed southern Illinois for several hours, reducing visibility to a quarter mile or less in many areas.
• Dense Fog in Illinois, November 8, 200619 eventsClearing skies and calm winds caused formation of widespread dense fog. Visibility was less than one quarter mile.
• Dense Fog in Illinois, October 17, 200719 eventsWidespread dense fog reduced visibility to one quarter mile or less. High pressure over the southern Appalachian Mountains produced a moist southeast low level wind flow just above the surface. Clear skies and nearly calm winds at the surface contributed to the fog.
• Dense Fog in Illinois, December 21, 200719 eventsWidespread dense fog reduced visibility to one-quarter mile or less. The lower levels of the atmosphere were very moist due to rainfall the previous day. A nearly stationary trough of low pressure extending northeast along the Ohio River resulted in a light convergent wind flow.
• Dense Fog in Illinois, December 18 to 19, 200819 eventsWidespread dense fog reduced visibility to one-quarter mile or less. The dense fog occurred along and just ahead of a warm front. Light east to southeast winds brought moist air over cold, icy ground.
• Dense Fog in Illinois, November 17, 201019 eventsWidespread dense fog developed over southern Illinois in association with clear skies and very moist southwest winds over cold ground. Visibility was less than one quarter mile on a widespread basis.
• Dense Fog in Illinois, May 3, 201019 eventsA weak ridge of high pressure extended from Illinois and Indiana southward across the Tennessee Valley. The combination of wet ground, calm winds, and clear skies produced areas of dense fog. Visibility was reduced to one-quarter mile or less at many locations.

Dense Fog everywhereEvery kind of event in Illinois

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24.