Illinois, Missouri Severe Extreme Heat Warning | Effective 07/27/2026 19:10
* WHAT...Dangerously hot conditions with heat index values up to 106.
* WHERE...In Illinois, Monroe IL and Saint Clair IL Counties. In
Missouri, Jefferson MO County.
* WHEN...Until 7 PM CDT Tuesday.
* IMPACTS...Heat related illnesses increase significantly during
extreme heat and high humidity events.
Drink plenty of fluids, stay in an air-conditioned room, stay out of
the sun, and check up on relatives and neighbors. Young children and
pets should never be left unattended in vehicles under any