National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Overcast

80°F

27°C

Humidity 87%
Wind Speed Calm
Barometer 29.92 in (1012.9 mb)
Dewpoint 76°F (24°C)
Visibility 10.00 mi
Heat Index85°F (29°C)
Last update 27 Jun 10:53 am CDT
Extended Forecast for

Cahokia / St. Louis, St. Louis Downtown Airport IL

Extreme Heat Watch June 28, 12:00pm until July 3, 12:00am
Click here for hazard details and duration
Extreme Heat Watch

  • Today

    Today: Showers and thunderstorms likely, mainly before 1pm. Partly sunny, with a high near 86. Southwest wind 3 to 6 mph. Chance of precipitation is 60%.

    High: 86 °F

    T-storms
    Likely

  • Tonight

    Tonight: A 40 percent chance of showers and thunderstorms, mainly between midnight and 5am. Partly cloudy, with a low around 71. South wind around 5 mph becoming calm in the evening.

    Low: 71 °F

    Chance
    T-storms

  • Sunday

    Sunday: Partly sunny, then gradually becoming sunny, with a high near 94. Heat index values as high as 107. South wind 5 to 9 mph.

    High: 94 °F

    Becoming
    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 75. South wind 6 to 9 mph.

    Low: 75 °F

    Mostly Clear

  • Monday

    Monday: Sunny and hot, with a high near 97. South wind 6 to 10 mph.

    High: 97 °F

    Hot

  • Monday Night

    Monday Night: Mostly clear, with a low around 76.

    Low: 76 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny and hot, with a high near 99.

    High: 99 °F

    Hot

  • Tuesday Night

    Tuesday Night: Clear, with a low around 76.

    Low: 76 °F

    Clear

  • Wednesday

    Wednesday: Sunny and hot, with a high near 97.

    High: 97 °F

    Hot

Detailed Forecast

Today
Showers and thunderstorms likely, mainly before 1pm. Partly sunny, with a high near 86. Southwest wind 3 to 6 mph. Chance of precipitation is 60%.
Tonight
A 40 percent chance of showers and thunderstorms, mainly between midnight and 5am. Partly cloudy, with a low around 71. South wind around 5 mph becoming calm in the evening.
Sunday
Partly sunny, then gradually becoming sunny, with a high near 94. Heat index values as high as 107. South wind 5 to 9 mph.
Sunday Night
Mostly clear, with a low around 75. South wind 6 to 9 mph.
Monday
Sunny and hot, with a high near 97. South wind 6 to 10 mph.
Monday Night
Mostly clear, with a low around 76.
Tuesday
Sunny and hot, with a high near 99.
Tuesday Night
Clear, with a low around 76.
Wednesday
Sunny and hot, with a high near 97.
Wednesday Night
Mostly clear, with a low around 77.
Thursday
Sunny, with a high near 96.
Thursday Night
Mostly clear, with a low around 76.
Friday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 95.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Cahokia / St. Louis, St. Louis Downtown Airport IL
 38.57°N 90.15°W (Elev. 407 ft)
Last Update:
11:36 am CDT Jun 27, 2026
Forecast Valid:
11am CDT Jun 27, 2026-6pm CDT Jul 3, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation