St. Louis, MO – Dangerous heat grips St. Louis and surrounding counties with highs in the upper 90s and heat indices topping 103° through the weekend, while the risk of thunderstorms rises by Sunday night. According to the National Weather Service, most of eastern and central Missouri—along with west central and southwest Illinois—will see only a slight chance of isolated storms overnight, but the threat for heavier storms increases from Saturday evening through Wednesday.
St. Louis, Saint Charles, Jefferson, and Metro East communities should plan for steamy afternoons, with outdoor events, travel, and back-to-school prep facing heat-related risks. Power grids and local utilities may be strained, especially in neighborhoods with limited tree cover or older infrastructure. For those spending time outdoors, limit strenuous activity during peak afternoon hours, stay hydrated, and never leave kids or pets in parked vehicles.
Sunday night into early next week brings the best chance for showers and thunderstorms, which could cause localized flooding and temporary road impacts. Keep an eye on local alerts, especially along I-70, I-64, and routes near the Missouri/Illinois border, where storm clusters may be strongest. Spotter activation is not expected right now, but updates could be issued quickly if conditions worsen.
Heat and storm chances are expected to persist through midweek. Stay weather-aware, check for updates, and plan outdoor activities with caution—this pattern looks set to linger a few more days.
Five Day St. Louis, MO Forecast:
- Friday: Sunny, heat index up to 103°. High 96°F, low 76°F
- Saturday: Sunny, very hot, south wind gusts. High 96°F, low 76°F
- Sunday: Mostly sunny, heat continues. High 94°F, low 75°F
- Monday: 30% chance of thunderstorms after 1 p.m., humid. High 93°F, low 74°F
- Tuesday: 30% chance of showers and storms, mainly after 1 p.m. High 92°F, low 74°F
