St. Louis, Missouri – The pavement is already warming under a hazy July sun, and the air feels heavier with each passing hour. By this afternoon, stepping outside across the St. Louis metro could feel closer to 108 degrees than the thermometer suggests, making even short errands more physically demanding.
Dangerous heat is building across eastern Missouri and southwest Illinois as a Heat Advisory remains in effect until 7 p.m. Tuesday. According to the National Weather Service in St. Louis, afternoon heat index values could climb as high as 108 degrees, creating an elevated risk of heat-related illness for anyone spending extended time outdoors.
Monday begins with patchy fog and a little lingering smoke before skies turn mostly sunny. Temperatures will rise to around 94 degrees, while oppressive humidity pushes the apparent temperature well into the triple digits. Drivers along Interstates 44, 55, 64, 70 and 270 should expect shimmering pavement and intense heat during the afternoon commute. Keep extra water in your vehicle and never leave children or pets inside parked cars.
The heat continues Tuesday with highs near 96 degrees and heat index values reaching 105 degrees before a cold front gradually approaches. A 30 percent chance of showers and thunderstorms develops Tuesday morning, offering only isolated relief. While widespread severe weather is not expected locally, a few stronger storms could produce gusty winds as the front moves through the Midwest.
By Wednesday, noticeably cooler and drier air arrives. Sunshine returns with a high near 85 degrees, making outdoor work and recreation much more comfortable. Thursday remains pleasant with highs in the mid-80s before scattered rain chances return later in the week.
Long-range outlooks suggest above-normal temperatures may build back into the region late next week, so this brief break from the heat may not last long.
Five-Day Forecast for St. Louis, Missouri
- Monday: Patchy fog early, then mostly sunny and hot. High 94°F. Low 79°F. Heat index near 103°F.
- Tuesday: Mostly sunny with a 30% chance of showers and thunderstorms before midday. High 96°F. Low 71°F. Heat index up to 105°F.
- Wednesday: Sunny and less humid. High 85°F. Low 66°F.
- Thursday: Mostly sunny. High 84°F. Low 67°F.
- Friday: Partly sunny with a 30% chance of showers before early afternoon. High 81°F.
