Warmer weather is expected to push heat index values to around 105 degrees across the region today, prompting an Extreme Heat Warning from Sunday afternoon, Aug. 9, 2026, through Wednesday, Aug. 12, 2026, according to the National Weather Service in St. Louis.
High temperatures are forecast in the mid-90s today. The warning comes as heat index values are expected to remain at levels that meet excessive heat criteria, the weather service said.
The National Weather Service in St. Louis says an Excessive Heat Warning is issued when the heat index is expected to be around 110 degrees for two days, or around 105 degrees for four consecutive days.
A slight chance of a few storms is forecast across northern counties Monday morning, Aug. 10, 2026. Otherwise, Monday is expected to be even hotter, with heat index values approaching 110 degrees.
The heat is expected to continue through Wednesday. A few disturbances are forecast to bring increasing chances of rain to the region for the remainder of the workweek and into the weekend.
Caution should be exercised during the Extreme Heat Warning for any outdoor activities. During an extreme heat warning, people are advised to stay in air-conditioned buildings, drink plenty of water even if they are not thirsty, and avoid heavy outdoor work during peak midday hours.
People also should check on vulnerable neighbors, never leave children or pets in cars, and know the signs of heat exhaustion and heat stroke.
To stay cool and hydrated, drink water regularly in small sips rather than waiting for thirst. Avoid alcohol, caffeine and very sugary drinks because they increase dehydration. Stay indoors with air conditioning whenever possible, or visit public cooling centers, libraries or malls if a home lacks air conditioning.
People should wear loose, lightweight and light-colored clothing and take cool showers or baths to lower core body temperature quickly.
Outdoor activities should be rescheduled to early mornings or late evenings when temperatures are lower. Those who must work outside should take frequent breaks in the shade or air conditioning.
Pets should have abundant fresh water and deep shade. Hot asphalt can burn their paws. No person or animal should be left inside a parked vehicle, where temperatures can rise to lethal levels within minutes.
