St. Louis, Missouri – Extreme heat will grip Missouri and southwest Illinois starting at noon Saturday, pushing heat index values up to 110° and prompting an urgent warning for millions.
According to the National Weather Service in St. Louis, the Extreme Heat Warning will remain in effect for St. Louis, Columbia, Jefferson City, and much of central and eastern Missouri, as well as Madison, St. Clair, Randolph, and Monroe counties in Illinois, until 7 p.m. Wednesday. Daytime highs and tropical humidity are expected to combine for several days of dangerous conditions.
Residents in St. Charles, Franklin, Boone, and Gasconade counties, along with the entire St. Louis metro, should prepare for increased risk of heat-related illnesses. Roads, sidewalks, and public transit may become hazardous for vulnerable populations. School activities, outdoor work, and summer events may face delays or cancellations. Local agencies urge everyone to drink water frequently, stay in air-conditioned spaces, and check on elderly relatives and neighbors.
Officials recommend avoiding strenuous activity between 11 a.m. and 7 p.m., wearing light clothing, and never leaving children or pets in vehicles. Extreme Heat Warnings remain active through Wednesday night. More advisories could follow if the heat persists into late week.
