Dense Fog Advisory

Full Alert Message

URGENT - WEATHER MESSAGE National Weather Service Chicago IL 302 AM CDT Mon Jul 27 2026 ...EXTREME HEAT WARNING REMAINS IN EFFECT UNTIL 9 PM CDT THIS EVENING... ...DENSE FOG ADVISORY IN EFFECT UNTIL 8 AM CDT THIS MORNING... * 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. PRECAUTIONARY/PREPAREDNESS ACTIONS... 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.