St. Louis, Missouri – Triple-digit heat returns to Missouri this week, with heat index values reaching up to 105° across the St. Louis metro by Wednesday afternoon.
According to the National Weather Service in St. Louis, a Heat Advisory remains in effect until 9 p.m. Thursday, covering most of eastern Missouri and southwest Illinois. Temperatures will reach 97°F Wednesday, with heat index values making it feel significantly hotter, especially along I-64 and I-70 corridors.
Residents should avoid strenuous activity from 1 to 5 p.m., when heat stress risk is highest. Stay hydrated, wear light clothing, and check on pets and vulnerable neighbors. Do not leave children or animals in parked cars, even briefly.
Storms could provide brief relief. Scattered thunderstorms are possible late Wednesday night into Thursday morning, though rainfall totals should remain low.
Cities including Chesterfield, Alton, Belleville, and Edwardsville will see consistent highs in the mid-to-upper 90s through Thursday. Nighttime temps remain warm in the upper 70s, offering little relief.
This week’s heat event is one of the first significant surges of summer 2025. The NWS warns this level of sustained heat can lead to heat exhaustion or stroke, particularly during the Wednesday and Thursday afternoon peaks.
⚠️ Warnings remain active through Thursday evening. Another round of heat and storms is possible into the weekend.
☀️ Five-Day Forecast for St. Louis, MO (June 24–29):
- Tuesday: High 96°F, scattered PM storms (30% chance)
- Wednesday: High 97°F, sunny and hot; storms possible late (30%)
- Thursday: High 96°F, mostly sunny, chance of PM storms (30%)
- Friday: High 96°F, slight storm chance (20%)
- Saturday: High 94°F, increasing clouds and storm risk (40%)
