Extreme Heat Watch

Locations Affected

Saint Louis, MO ∙ O'Fallon, MO ∙ Saint Charles, MO ∙ Florissant, MO ∙ Saint Peters, MO ∙ Lenzburg, IL ∙ Mitchell, IL ∙ Cottleville, MO ∙ Town and Country, MO ∙ Imperial, MO

Full Alert Message

URGENT - WEATHER MESSAGE National Weather Service St Louis MO 156 PM CDT Thu Jun 19 2025 ...EXTREME HEAT WATCH REMAINS IN EFFECT FROM SATURDAY AFTERNOON THROUGH TUESDAY EVENING... * WHAT...Dangerously hot conditions with heat index values up to 108 possible. * WHERE...In Illinois, Jersey IL, 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...From Saturday afternoon through Tuesday evening. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events. 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. Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes. Monitor the latest forecasts and warnings for updates.

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