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.

Fair

80°F

27°C

Humidity 82%
Wind Speed W 6 mph
Barometer 29.76 in (1007.4 mb)
Dewpoint 74°F (23°C)
Visibility 10.00 mi
Heat Index85°F (29°C)
Last update 27 Jul 11:53 pm CDT
Extended Forecast for

Mascoutah IL

Extreme Heat Warning July 28, 12:22am until July 28, 07:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning July 28, 12:22am until July 28, 07:00pm

    NOW until 7:00pm Tue

    Extreme Heat Warning

  • Overnight

    Low: 78 °F

    Mostly Clear

  • Tuesday

    Tuesday: Increasing clouds, with a high near 92. Heat index values as high as 105. Northwest wind 6 to 8 mph becoming north in the afternoon.

    High: 92 °F

    Increasing
    Clouds

  • Tuesday Night

    Tuesday Night: Mostly cloudy during the early evening, then gradual clearing, with a low around 68. Northeast wind 3 to 8 mph.

    Low: 68 °F

    Gradual
    Clearing

  • Wednesday

    Wednesday: Sunny, with a high near 86. Calm wind becoming northeast 5 to 7 mph in the morning.

    High: 86 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Clear, with a low around 66. Northeast wind around 6 mph becoming calm in the evening.

    Low: 66 °F

    Clear

  • Thursday

    Thursday: Sunny, with a high near 88.

    High: 88 °F

    Sunny

  • Thursday Night

    Thursday Night: A 20 percent chance of showers after 1am. Partly cloudy, with a low around 69.

    Low: 69 °F

    Partly Cloudy
    then Slight
    Chance
    Showers

  • Friday

    Friday: A chance of showers, with thunderstorms also possible after 1pm. Partly sunny, with a high near 86. Chance of precipitation is 40%.

    High: 86 °F

    Chance
    Showers

Detailed Forecast

Overnight
Mostly clear, with a low around 78. West wind 3 to 6 mph.
Tuesday
Increasing clouds, with a high near 92. Heat index values as high as 105. Northwest wind 6 to 8 mph becoming north in the afternoon.
Tuesday Night
Mostly cloudy during the early evening, then gradual clearing, with a low around 68. Northeast wind 3 to 8 mph.
Wednesday
Sunny, with a high near 86. Calm wind becoming northeast 5 to 7 mph in the morning.
Wednesday Night
Clear, with a low around 66. Northeast wind around 6 mph becoming calm in the evening.
Thursday
Sunny, with a high near 88.
Thursday Night
A 20 percent chance of showers after 1am. Partly cloudy, with a low around 69.
Friday
A chance of showers, with thunderstorms also possible after 1pm. Partly sunny, with a high near 86. Chance of precipitation is 40%.
Friday Night
Showers likely and possibly a thunderstorm. Mostly cloudy, with a low around 70. Chance of precipitation is 60%.
Saturday
A chance of showers, with thunderstorms also possible after 1pm. Partly sunny, with a high near 82. Chance of precipitation is 50%.
Saturday Night
A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 68.
Sunday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 85.
Sunday Night
Mostly clear, with a low around 68.
Monday
A 20 percent chance of showers. Sunny, with a high near 85.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Mascoutah IL
 38.5°N 89.81°W (Elev. 427 ft)
Last Update:
11:51 pm CDT Jul 27, 2026
Forecast Valid:
12am CDT Jul 28, 2026-6pm CDT Aug 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