St. Louis, MO – Missouri residents should brace for a mid-September heat surge as St. Louis temperatures climb into the 90s by Wednesday. Commuters on I-70 and I-64 could face added risks from heat-related vehicle breakdowns during the late-week warmup. Staying hydrated and checking tire pressure will be key safety measures for drivers.
According to the National Weather Service in St. Louis, partly sunny skies Tuesday give way to highs near 90 degrees Wednesday and 92 Thursday. Friday will peak at 94 before any chance of relief arrives late in the weekend. Winds remain light, but the combination of heat and sunshine could strain outdoor workers and vulnerable populations.
City neighborhoods from downtown to North County will experience the same hot stretch. Cooling centers remain open across St. Louis for residents without reliable air conditioning. Health officials urge limiting outdoor activities during peak afternoon hours and keeping pets indoors whenever possible.
While the weather stays calm, the prolonged heat may affect schools, road crews, and public events through Friday. Emergency managers remind families to review severe weather kits ahead of fall storm season, which often ramps up later in September.
The warm spell is expected to ease slightly by Sunday night, when clouds and a 20 percent chance of showers enter the region.
Five Day Forecast for St. Louis, Missouri
- Wednesday: Sunny, high near 90, low 64
- Thursday: Sunny, high 92, low 66
- Friday: Sunny, high 94, low 69
- Saturday: Mostly sunny, high 96, low 71
- Sunday: Partly cloudy, 20% chance showers, high 96, low 70
