St. Louis rolled into Tuesday, June 9, 2026, under a muggy, mostly cloudy sky, and the air is thick enough to feel every degree. Afternoon highs are headed for the lower 90s, but the humidity will push the heat index into the triple digits during peak hours. Early showers and thunderstorms are in the mix this morning and could briefly slow the commute before the sun muscles back through the clouds.
The National Weather Service has a Heat Advisory in effect from 12:00 p.m. to 10:00 p.m. CDT on Tuesday, June 9, 2026, with forecasters calling for heat index values around 105 to 108 degrees. They also flag the potential for stronger storms later in the week. NWS St. Louis recommends drinking plenty of fluids, skipping long stretches of outdoor work during the hottest part of the day, and checking in on neighbors and vulnerable adults.
Afternoon Heat and Short-Term Rain
Once any morning showers move out, skies should turn partly sunny, setting the stage for an afternoon high near 92 degrees with a light southwest breeze at about 3 to 8 mph. Any storms that pop up before 1:00 p.m. CDT are expected to be brief, but they could still drop heavy rain and bring gusty winds. A Flood Watch that had been posted earlier has been canceled, which takes some pressure off in terms of flash flooding, although localized heavy downpours are still on the table.
Severe Storm Risk Wednesday-Thursday
Heat will build even more on Wednesday and Thursday, with highs pushing into the mid 90s and a renewed chance for stronger thunderstorms. Forecasts point to the possibility of large hail and damaging winds during the late afternoon and evening on both Wednesday and Thursday. If you have outdoor evening plans on Wednesday, June 10, 2026, or Thursday, June 11, 2026, keep an eye on the sky and be ready to move indoors quickly. Late-week storms could also pack locally heavy rain along with the wind and hail threat.
How to Stay Cool
For anyone who needs a break from the heat, public cooling locations are available. You can call 2-1-1 to find the nearest option, or check whether local libraries and community centers are open as cooling centers. The city also offers programs to help seniors with window-unit installation. For a full rundown of cooling centers, pet safety tips, and emergency contacts, visit the City of St. Louis.
If you are out and about today, shift strenuous outdoor tasks to early morning or after sunset, keep water with you, and never leave people or pets in parked cars, even for a short time. We will post updates if advisories change through the week.
