Weather Alerts For O'Fallon, IL

# HEADLINE -------------------- EXTREME HEAT WARNING REMAINS IN EFFECT UNTIL 8 PM CDT SATURDAY # DETAILS -------------------- WHAT Dangerously hot conditions with heat index values up to 108. WHERE In Illinois, Madison IL, Monroe IL, and Saint Clair IL Counties. In Missouri, Jefferson MO, Saint Charles MO, Saint Louis City MO, and Saint Louis MO Counties. WHEN Until 8 PM CDT Saturday. IMPACTS Heat related illnesses increase significantly during extreme heat and high humidity events. ISSUED AT Thursday, September 3, 2026 at 2:45 PM CDT ISSUED BY National Weather Service St Louis MO HEADER URGENT - WEATHER MESSAGE # PRECAUTIONARY/PREPAREDNESS ACTIONS -------------------- People in the Saint Louis Metropolitan Area can get information about cooling centers or energy assistance related to the excessive heat by calling the United Way of Greater Saint Louis at 800-427-4626, or if calling from a land line phone dial 2-1-1. You can also call Cool Down Saint Louis at 314-241-7668. # AREAS AFFECTED -------------------- Jefferson MO, Madison IL, Monroe IL, Saint Charles MO, Saint Clair IL, Saint Louis City MO, Saint Louis MO Including the cities of Belleville, Alton, Edwardsville, Saint Louis, Cahokia, and Saint Charles

Pollen Index: 11.7 Pollen Level: high Predominant Pollen: Ragweed, Chenopods and Nettle. Based on past pollen counts and expected weather conditions, pollen levels for Friday will remain stable in the extremely high range. This is a result of stable temperatures. Pollen producing plants are at a relatively steady level of pollination at this time.