St. Louis woke up Sunday, July 19, to clear, muggy skies and a sticky 77°F start. Mostly sunny conditions are expected to hang on through midmorning, but the quiet will not last: scattered showers and thunderstorms are likely to pop up after noon as temperatures climb toward a high near 91°F.
Heat Advisory Through Tuesday
The National Weather Service St. Louis has a Heat Advisory in place through 7 p.m. CDT Tuesday, July 21, warning that heat index values will push into the low 100s. For today, the high is forecast near 91°F with heat index values up to around 101°F. Monday looks even more uncomfortable, with heat indices expected to reach about 103°F, creating conditions where prolonged outdoor work or play can quickly become hazardous.
Afternoon Storms Possible
Scattered showers and thunderstorms are expected to develop after noon, with the best chances across central and southeast Missouri and parts of southwest Illinois. Any storm that does fire up could produce brief heavy downpours and gusty winds, though forecasters are not calling for widespread severe weather. If you have outdoor plans, it is wise to get the strenuous stuff done in the morning or have a quick escape route indoors once the skies start to darken.
Smoke, Air Quality And Where To Cool Off
Forecasters also note that a thin plume of Canadian wildfire smoke may drift into the region this afternoon and evening, which could knock down visibility a bit and nudge air quality lower in spots.
For anyone needing a break from the heat, the city maintains a list of cooling centers where residents can get relief. Downtown options include the Central Library at 1301 Olive Street and the Five Star Senior Center at 2832 Arsenal St. You can find the full list at the City of St. Louis.
