St. Louis woke up already sweating this morning, clear skies and all, with temperatures sitting around 82°F and the humidity firmly in the muggy zone. The city remains under a Heat Advisory until 7:00 PM CDT Tuesday, July 21, 2026, with a high near 96°F on tap and heat index readings expected in the low to mid 100s. That kind of heat can make midday outdoor activity genuinely risky, not just uncomfortable. If you have to be outside, try to tackle heavy work in the early morning or after sunset and drink plenty of water. And as always, never leave children or pets unattended in parked cars, not even for a few minutes.
Afternoon Heat And Storm Chances
There is a slight chance of showers and a few thunderstorms before 10:00 a.m., mainly over southern suburbs, but coverage looks limited so most neighborhoods will not see much in the way of cooling. Northwest winds will pick up to 6 to 14 mph this afternoon, with gusts that could approach 20 mph. The breeze may take the edge off a little, but it will not be enough to cancel out the heat index. National Weather Service forecasters are keeping the Heat Advisory in place and say heat index values could reach about 105°F across parts of the metro.
When Relief Arrives
A cold front is expected to push through tonight into Wednesday, bringing cooler, drier air and knocking highs down into the mid 80s on Wednesday, July 22, 2026. Humidity should drop as well, which will make both Wednesday and Thursday feel noticeably more comfortable across the region. Rain chances return later in the week, with isolated heavier storms possible on Friday, so keep an eye on updated forecasts if you have outdoor plans.
Cooling Options And Safety
County and nonprofit cooling sites are open across the metro, and The Salvation Army’s Family Haven at 10740 Page Avenue is operating as a 24/7 cooling and shelter location for people who need a safe place. For a full roster of partner agencies and local sites, call 2 1 1 or visit Heat Up St. Louis. If you work outdoors, try to reschedule strenuous tasks to cooler hours and take frequent breaks in the shade with plenty of water.
