Extreme Heat Watch

Locations Affected

Saint Louis, MO ∙ O'Fallon, MO ∙ Saint Charles, MO ∙ Florissant, MO ∙ Saint Peters, MO ∙ Fults, IL ∙ Hamel, IL ∙ Percy, IL ∙ Hartford, IL ∙ Gard, IL

Full Alert Message

URGENT - WEATHER MESSAGE National Weather Service St Louis MO 1227 PM CDT Sun Aug 30 2026 ...EXTREME HEAT WATCH IN EFFECT FROM MONDAY AFTERNOON THROUGH FRIDAY EVENING... * WHAT...Dangerously hot conditions with heat index values of 102 to 108 degrees, and morning lows from 75 to 80 degrees, possible for several consecutive days. * WHERE...In Illinois, Clinton IL, Washington IL, Madison IL, Monroe IL, Randolph IL, and Saint Clair IL Counties. In Missouri, Saint Charles MO, Saint Louis City MO, and Saint Louis MO Counties. * WHEN...From Monday afternoon through Friday evening. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events. * ADDITIONAL DETAILS...In addition to near-record afternoon temperatures, warm morning lows may provide little relief, especially Wednesday through Friday. 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. Monitor the latest forecasts and warnings for updates.

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