St. Louis/ Weather & Environment

St. Louis Sizzles at 96 Before Weekend Storms Break the Heat

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Published on September 18, 2026
St. Louis Sizzles at 96 Before Weekend Storms Break the HeatSource: Google Street View

St. Louis is heading into another day of dangerous heat, with low clouds expected early Friday before lifting and scattering later. The temperature is expected to climb to 96 degrees, while the heat index could reach around 105 before storms and a major cooldown arrive next week.

Heat Advisory Stretches Through Saturday

The National Weather Service has a Heat Advisory in effect for St. Louis through 8 p.m. Saturday, with high humidity making outdoor conditions feel significantly hotter. Friday will see clouds lift and scatter later, with a few afternoon thunderstorms possible, according to the National Weather Service.

Saturday will bring another high near 96 degrees, though the heat index should be near 100. The update extends the heat pattern covered in an earlier Hoodline forecast, while adding a clearer timeline for the storms and cooler air ahead.

Ozone Alert Adds Another Reason To Take It Easy

An air quality alert is also scheduled for the St. Louis metropolitan area from 10 a.m. to 8 p.m. Friday because of elevated ozone levels.

People looking for relief during the hottest part of the day can check the City of St. Louis cooling sites.

Storms Arrive Before Temperatures Drop

Sunday will remain warm, with temperatures in the low to mid-90s and a 20% chance of afternoon showers or thunderstorms. Rain chances increase Sunday night, followed by a wetter Monday with showers and thunderstorms likely and highs in the upper 70s.

The rain does not look nonstop, but several rounds could move through as a slow-moving front crosses the region. Locally heavy rain is possible where storms linger, so outdoor plans may need a backup from Sunday evening through Monday.

Relief Finally Shows Up Tuesday

By Tuesday, precipitation chances should end by morning, with noticeably cooler temperatures. Wednesday and Thursday should remain cooler.