St. Louis woke up Tuesday, June 23, 2026, in a gray blur, with widespread fog, cool air in the mid 50s, and visibility in some low-lying spots dropping to less than a quarter mile. The murk will not last. Forecasters expect the fog to burn off after sunrise, letting sunshine take over and push afternoon highs into the low 80s.
Foggy Mornings, Sunny Afternoons
Calm overnight winds and a saturated layer of air near the ground helped fog pool along river valleys and other low spots before daybreak. As the sun climbs and light east winds return, those thicker pockets should erode fairly quickly and give way to mostly sunny skies.
By this afternoon, St. Louis should top out near 82°F with gentle northeast winds around 3 mph. That is on the cool side for late June and a brief break from the more typical early-summer steam.
Storms and Flooding Risk Thursday–Friday
The quiet stretch will not last long. A more active pattern builds in late this week, with showers and thunderstorms likely from Thursday into Friday and rain chances climbing into the 70 to 80 percent range. Several rounds of storms could bring heavy, slow-moving downpours and localized flash flooding, especially in low-lying neighborhoods and near creeks.
The National Weather Service St. Louis is urging residents to steer clear of driving through standing water and to keep an eye on updated forecasts as the storm setup gets closer.
Warm Return Late Weekend
After the soggy stretch, summer roars back. A warm ridge is expected to build over the region, pushing temperatures into the 90s by Sunday and Monday, with highs around 94 to 96°F. Humidity could help send heat indices over the 100°F mark, turning afternoons into full-on heat tests.
If that warm spell arrives as forecast, vulnerable residents should plan ahead for hotter afternoons and consider using public cooling options. The City of St. Louis lists designated cooling centers across the city. Keep water handy and check on neighbors when the heat begins to spike.
What To Know For Commuters
This morning’s fog is expected to clear before the bulk of the commute, but drivers should still allow extra time until visibility fully improves and watch for slower traffic in fog-prone corridors.
Later in the week, heavy rain and thunderstorms could slow major roads and disrupt transit schedules. Travelers are advised to check official updates before heading out and to avoid walking or driving through flooded streets, no matter how shallow they look.
