St. Louis is starting Sunday under clear skies and almost no wind, but the quiet morning will give way to a serious heat run, with highs rising from 96 today to 100 Monday and 101 Tuesday through Thursday. Overnight relief will be limited, with lows reaching 80 degrees several nights in a row.
Heat Builds Through Thursday
According to the National Weather Service, Sunday stays sunny and dry with a south wind of 6 to 9 mph. Monday's high near 100 could feel like 102, while Tuesday, Wednesday and Thursday are each forecast to reach about 101; no watches, warnings or advisories are currently listed.
The updated outlook is a sharper turn from the earlier week-ahead picture, pushing the hottest temperatures into a longer run. An earlier Hoodline report noted the initial 99-to-100-degree stretch, but the newest forecast keeps triple-digit heat in place through Thursday and still has Friday near 99.
Warm Nights Leave Little Relief
Sunday night dips to 74, followed by lows around 77 Monday and 80 Tuesday through Thursday. Those warm nights mean the city will get less of a cooldown between hot afternoons, making air conditioning, hydration and regular breaks especially important.
The heat will also come close to daily records at St. Louis Lambert, including 103 degrees Monday, 104 Tuesday, and 101 Wednesday and Thursday. The weather service describes the pattern as record-threatening and potentially dangerous, while noting that changing humidity will determine how oppressive the heat feels.
Small Storm Chance Arrives Late
Rain is not part of the main story through Thursday, with precipitation chances at or near zero. Friday stays mostly sunny near 99, then a slight chance of showers and thunderstorms appears Friday evening into early Saturday; another 20% chance returns after 1 p.m. Saturday, when the high is forecast near 96.
Cooling Resources Remain Available
St. Louis city officials maintain a list of cooling sites and recommend calling ahead because hours can change; residents can also call 2-1-1 for regional options. The city's cooling-center guide also advises checking on older neighbors and others who may need help during extreme heat.
For Sunday through Thursday, the practical plan is simple: schedule strenuous outdoor activity early, drink water often, take breaks in shade or air conditioning, and never leave children or pets in a parked car. The forecast is dry enough for outdoor plans, but a week of 100-degree afternoons and 77-to-80-degree nights is not one to take lightly.
