Extreme Heat Warning for Illinois and Missouri
This alert is no longer in effect.
NOAA issued it on August 9, 2026, 2 weeks ago. Warnings of this kind stay in effect for hours to a few days, so this page is a historical record of what was issued, not a current warning. For conditions where you are right now, check weather.gov (US), weather.gc.ca (Canada), the Met Office (UK), or the Bureau of Meteorology (Australia).
Areazine synthesizes this NWS weather alert directly from NOAA's official public data feed. See our methodology for full source attribution and refresh cadence.
An Extreme Heat Warning is in effect from noon August 9 until 8 PM CDT August 12 for portions of south central and southwest Illinois and central and east central Missouri, with heat index values up to 109.
Read this weather record in 30 seconds
- Record type
- Extreme Heat Warning
- Affected area
- South Central and Southwest Illinois, Central and East Central Missouri
- Issued
- August 9, 2026
- Issuing authority
- NWS St Louis MO
Heat notices are time-bound and location-specific. Confirm the current forecast and local public-health guidance before relying on this archived record.
Record status: historical. It was issued 2 weeks ago; use the issuing agency's live warning service for current conditions in South Central and Southwest Illinois, Central and East Central Missouri.
Alert Details
Extreme Heat Warning issued by NWS St Louis MO on August 9 at 1:05AM CDT. The alert is effective from noon today through 8 PM CDT Wednesday.
Affected Areas
Portions of south central and southwest Illinois and central and east central Missouri, including Clinton, Washington, Randolph, Madison, St. Clair, Monroe, Boone, Moniteau, Cole, Osage, Callaway, Montgomery, Gasconade, Warren, St. Charles, Franklin, St. Louis, St. Louis City and Jefferson counties.
What You Should Do
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. Take extra precautions if working or spending time outside. Reschedule strenuous activities to early morning or evening when possible. Wear lightweight and loose fitting clothing. Schedule frequent rest breaks in shaded or air conditioned environments during outdoor work. Anyone overcome by heat should be moved to a cool and shaded location. Call 911 for heat stroke emergencies. Saint Louis Metropolitan Area residents can call United Way of Greater Saint Louis at 800-427-4626 or Cool Down Saint Louis at 314-241-7668 for cooling center information.
Expected Conditions
Dangerously hot conditions with heat index values up to 109 expected.
Timeline
The warning is in effect from noon August 9 to 8 PM CDT August 12.
Original source: NOAA Official Notice ↗
Related Weather Alerts
All Weather Alerts →Nationwide notices with similar length or severity timing 8
Two Areazine-derived peer sets for this NWS weather alert: nearest notices by body length and by same severity near the same agency date. Peers come from other categories so they are not the same-feed Related list above.
Similar body length
Nearest notices by article body length (1,416 characters here).
Similar severity timing
Same severity (high) notices issued closest in time to August 9, 2026.
Frequently Asked Questions
Common questions about this NWS weather alert.