ST. LOUIS, GLEN CARBON/MARYVILLE, IL. - The National Weather Service in St. Louis has issued an Extreme Heat Watch for Madison and St. Clair counties and nearby areas from Sunday afternoon, June 28 through Thursday evening, July 2, 2026, warning that heat index values of 105 to 110 are possible as a prolonged stretch of heat and humidity begins.The watch was issued at 1:59 a.m. CDT Saturday, June 27, 2026, and covers St. Clair, Madison and Monroe counties in Illinois, along with Jefferson, St. C...