By VOTP News STL Staff
September 18, 2026
ST. LOUIS — Dangerous heat and poor air quality are expected across the St. Louis region Friday.
The forecast calls for mostly sunny, hot and humid conditions, with a high near 95 degrees and an overnight low near 71. An isolated afternoon thunderstorm is possible.
The National Weather Service has a Heat Advisory in effect for St. Louis and surrounding communities through 8 p.m. Saturday. Heat index values could reach 107 degrees.
An Orange Air Quality Alert is also in effect from 10 a.m. to 8 p.m. Friday. The alert means ozone levels may be unhealthy for children, older adults and people with respiratory conditions. Those groups should consider reducing prolonged outdoor activity.
Residents should drink plenty of water, limit strenuous outdoor activity during the hottest part of the day and check on relatives and neighbors.
Sources: National Weather Service St. Louis, Heat Advisory and Air Quality Alert.
