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

78°F

26°C

Humidity 90%
Wind Speed S 5 mph
Barometer 29.96 in (1013.9 mb)
Dewpoint 75°F (24°C)
Visibility 10.00 mi
Heat Index80°F (27°C)
Last update 30 Jun 12:53 am CDT
Extended Forecast for

Mascoutah IL

Extreme Heat Warning June 30, 01:44am until July 3, 10:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning June 30, 01:44am until July 3, 10:00pm

    NOW until 10:00pm Fri

    Extreme Heat Warning

  • Overnight

    Low: 74 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 96. Heat index values as high as 111. Light south wind increasing to 5 to 9 mph in the morning.

    High: 96 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Clear, with a low around 76. South wind 5 to 9 mph becoming calm after midnight.

    Low: 76 °F

    Clear

  • Wednesday

    Wednesday: Sunny, with a high near 96. Heat index values as high as 110. Southwest wind 3 to 8 mph.

    High: 96 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Clear, with a low around 77. South wind 5 to 9 mph becoming calm after midnight.

    Low: 77 °F

    Clear

  • Thursday

    Thursday: Sunny, with a high near 96.

    High: 96 °F

    Sunny

  • Thursday Night

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

    Low: 76 °F

    Mostly Clear

  • Friday

    Friday: A 40 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 95.

    High: 95 °F

    Sunny then
    Chance
    T-storms

Detailed Forecast

Overnight
Mostly clear, with a low around 74. South wind 5 to 7 mph.
Tuesday
Sunny, with a high near 96. Heat index values as high as 111. Light south wind increasing to 5 to 9 mph in the morning.
Tuesday Night
Clear, with a low around 76. South wind 5 to 9 mph becoming calm after midnight.
Wednesday
Sunny, with a high near 96. Heat index values as high as 110. Southwest wind 3 to 8 mph.
Wednesday Night
Clear, with a low around 77. South wind 5 to 9 mph becoming calm after midnight.
Thursday
Sunny, with a high near 96.
Thursday Night
Mostly clear, with a low around 76.
Friday
A 40 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 95.
Friday Night
A 30 percent chance of showers and thunderstorms, mainly before 1am. Partly cloudy, with a low around 75.
Independence Day
A 30 percent chance of showers and thunderstorms, mainly after 1pm. Mostly sunny, with a high near 94.
Saturday Night
A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74.
Sunday
A 40 percent chance of showers and thunderstorms. Mostly sunny, with a high near 92.
Sunday Night
A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 73.
Monday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 90.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Mascoutah IL
 38.52°N 89.81°W (Elev. 423 ft)
Last Update:
1:21 am CDT Jun 30, 2026
Forecast Valid:
1am CDT Jun 30, 2026-6pm CDT Jul 6, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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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