Tomorrow | Weather | St. Louis, Missouri

Active Weather Warnings
Tuesday, September 15, 2026
Sunny with a Chance of Thunderstorms
Day 99°
Night 72°
Precipitation 55 %
Wind 8 mph
UV Index (0 - 11+) 6
Weather Forecast History
Last Year's Weather on This Day (September 15, 2025)
Cloudy Night

Day

97°

Night

64°

Wind

5 mph

Precipitation

1 %

Weather Alerts and Warnings for

Moderate Expected Likely

Heat Advisory

Heat Advisory issued September 14 at 11:30AM CDT until September 15 at 7:00PM CDT by NWS St Louis MO
Sep 15, 11:00 AM Sep 15, 7:00 PM
WHAT: Heat index values up to 107 expected.

WHERE: Portions of south central and southwest Illinois and
central, east central, and southeast Missouri.

WHEN: From 11 AM to 7 PM CDT Tuesday.

IMPACTS: Hot temperatures and high humidity may cause heat
illnesses.
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Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Young children and pets should never be left unattended in vehicles under any circumstances. Take extra precautions if you work or spend time outside. When possible reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear lightweight and loose fitting clothing when possible. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency! Call 9 1 1. People in the Saint Louis Metropolitan Area can get information about cooling centers or energy assistance related to the excessive heat by calling the United Way of Greater Saint Louis at 800-427-4626, or if calling from a land line phone dial 2-1-1. You can also call Cool Down Saint Louis at 314-241-7668.
Updated: Sep 14, 1:19 PM Source: NWS Alert