St. Louis drivers and residents face another day of near-record September heat Sunday before a noticeable cool down begins midweek. Afternoon highs will push near 99 degrees, and the heat index may briefly top 100, raising safety concerns for outdoor activity. Officials urge residents to stay hydrated and limit time outside during peak afternoon hours.
According to the National Weather Service in St. Louis, a 20 percent chance of showers and thunderstorms could develop after 4 p.m. Sunday, especially along I-70 and in the northern metro. Overnight, conditions will stay warm and muggy with lows near 72, but storm chances increase slightly before midnight.
Monday brings another hot, mostly sunny day, with temperatures near 94. Winds will pick up slightly, offering limited relief. By Tuesday and Wednesday, skies remain mostly sunny and highs again touch the mid-90s, but a shift begins late Wednesday night with showers possible.
By Thursday, rain chances increase sharply, with a 50 percent chance of showers and thunderstorms through the afternoon. This system signals the start of a cooler, fall-like pattern that lingers into next weekend. Highs will dip into the mid-80s by Friday and Saturday, making outdoor events and travel more comfortable.
Residents should monitor local alerts as storms could affect commutes and evening activities, especially along major highways. Heat and humidity remain the immediate threat through midweek, but fall relief is finally on the horizon.
Five Day Forecast for St. Louis, Missouri
- Monday: Mostly sunny, high near 94.
- Tuesday: Sunny, high near 94. Low near 68.
- Wednesday: Sunny, high near 94. Evening showers possible.
- Thursday: Showers and thunderstorms likely, high near 86.
- Friday: Mostly sunny, high near 86.
