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

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Fair

65°F

18°C

Humidity 68%
Wind Speed SE 5 mph
Barometer 29.91 in (1012.5 mb)
Dewpoint 54°F (12°C)
Visibility 10.00 mi
Last update 30 Sep 5:53 am CDT
Extended Forecast for

Mascoutah IL

  • Today

    Today: Partly sunny, with a high near 91. Light and variable wind becoming south 5 to 10 mph in the morning. Winds could gust as high as 20 mph.

    High: 91 °F

    Partly Sunny

  • Tonight

    Tonight: Mostly cloudy, with a low around 71. South wind around 8 mph.

    Low: 71 °F

    Mostly Cloudy

  • Thursday

    Thursday: A slight chance of showers between 3pm and 4pm, then a slight chance of showers and thunderstorms after 4pm. Mostly cloudy, with a high near 89. Southwest wind 9 to 14 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.

    High: 89 °F

    Partly Sunny
    then Slight
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms, then showers and possibly a thunderstorm after 1am. Low around 66. Southwest wind around 6 mph becoming calm in the evening. Chance of precipitation is 80%.

    Low: 66 °F

    Chance
    Showers then
    Showers

  • Friday

    Friday: Showers likely, mainly before 1pm. Mostly cloudy, with a high near 73. North wind 7 to 13 mph. Chance of precipitation is 60%.

    High: 73 °F

    Showers
    Likely

  • Friday Night

    Friday Night: Partly cloudy, with a low around 55.

    Low: 55 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 71.

    High: 71 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 52.

    Low: 52 °F

    Partly Cloudy

  • Sunday

    Sunday: Sunny, with a high near 74.

    High: 74 °F

    Sunny

Detailed Forecast

Today
Partly sunny, with a high near 91. Light and variable wind becoming south 5 to 10 mph in the morning. Winds could gust as high as 20 mph.
Tonight
Mostly cloudy, with a low around 71. South wind around 8 mph.
Thursday
A slight chance of showers between 3pm and 4pm, then a slight chance of showers and thunderstorms after 4pm. Mostly cloudy, with a high near 89. Southwest wind 9 to 14 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.
Thursday Night
A chance of showers and thunderstorms, then showers and possibly a thunderstorm after 1am. Low around 66. Southwest wind around 6 mph becoming calm in the evening. Chance of precipitation is 80%.
Friday
Showers likely, mainly before 1pm. Mostly cloudy, with a high near 73. North wind 7 to 13 mph. Chance of precipitation is 60%.
Friday Night
Partly cloudy, with a low around 55.
Saturday
Mostly sunny, with a high near 71.
Saturday Night
Partly cloudy, with a low around 52.
Sunday
Sunny, with a high near 74.
Sunday Night
Mostly clear, with a low around 49.
Monday
Sunny, with a high near 68.
Monday Night
Clear, with a low around 45.
Tuesday
Sunny, with a high near 70.
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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:
5:31 am CDT Sep 30, 2026
Forecast Valid:
6am CDT Sep 30, 2026-6pm CDT Oct 6, 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