Illinois Moderate Dense Fog Advisory | Effective 07/27/2026 03:48

Headline: 
Dense Fog Advisory issued July 27 at 5:48AM CDT until July 27 at 8:00AM CDT by NWS Chicago IL
Event: 
Dense Fog Advisory
Urgency: 
Expected
Effective: 
July 27, 2026 - 3:48am
Expires: 
July 27, 2026 - 2:00pm
Description: 
* WHAT...For the Extreme Heat Warning, dangerously hot conditions with peak heat index values 110 to locally over 115 degrees expected. For the Dense Fog Advisory, visibility less than one quarter mile in dense fog. * WHERE...Livingston, De Kalb, La Salle, Lee, Ogle, Winnebago, and Grundy Counties. * WHEN...For the Extreme Heat Warning, until 9 PM CDT this evening. For the Dense Fog Advisory, until 8 AM CDT this morning. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events. Low visibility could make driving conditions hazardous.
Instruction: 
Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. If driving, slow down, use your headlights, and leave plenty of distance ahead of you.
Area Description: 
Winnebago; Ogle; Lee; De Kalb; La Salle; Grundy; Livingston
Forcast Office: 
NWS Chicago IL