Extreme Heat Warning Covers Central, East Central and Southeast Missouri and South Central, Southwest Illinois
Heat index values up to 109 are expected, with the warning in effect until 9:00 PM on August 16, 2026, according to the National Weather Service office in St. Louis.
3 reports on this incident · first at Aug 16, 2026, 6:50 p.m. ET
Earlier reports
Aug 16, 2026, 6:53 p.m. ET
Extreme Heat Warning Issued for Portions of Missouri and Illinois
The National Weather Service office in St. Louis has raised the hazard level to an Extreme Heat Warning on August 16, 2026, for central, east central, and southeast Missouri, as well as portions of south central and southwest Illinois. Medical Daily reported that the warning is in effect until 9:00 p.m. on August 16, 2026, with dangerously hot conditions and heat index values up to 109.
Heat-related illnesses increase significantly during combined extreme heat and high humidity, according to Medical Daily. Recommended precautions include drinking fluids, staying in air-conditioned spaces, staying out of the sun, and checking on relatives and neighbors.
Aug 16, 2026, 6:50 p.m. ETFirst report
NWS Warns Heat Illnesses Will Increase Significantly in Illinois and Missouri
Heat-related illnesses increase significantly during combined extreme heat and high humidity, the National Weather Service warned on August 16, 2026. The risk accompanies an Extreme Heat Warning issued by the National Weather Service office in St. Louis for portions of south central and southwest Illinois, as well as central, east central, and southeast Missouri.
The warning covers dangerously hot conditions with heat index values up to 109. The alert remains active until it expires at 9:00 PM on August 16, 2026.
Recommended precautions include drinking fluids, staying in air-conditioned spaces, staying out of the sun, and checking on relatives and neighbors.
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Revision history
- Version 217 Aug 2026, 14:46current
Rebuilt the headline so it leads with the hazard (Extreme Heat Warning) and the specific areas named in the record, removing the issuing office from the front of the line; moved the issuing office and the 9:00 PM August 16, 2026 expiration into the dek. Kept the heat index figure as "109" exactly, retained all medicaldaily.com attributions, impacts and precautions, and dropped the unsupported claim that the warning was issued on August 16 in favor of the stated effective period.
- Version 116 Aug 2026, 22:50current
First published.
- Version 116 Aug 2026, 22:42
First published.
- Version 116 Aug 2026, 22:53current
First published.
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