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Areas of Dangerous Heat and Heavy Rainfall Today

Hot temperatures and high humidity are forecast to continue across the mid-Mississippi Valley today. Heat Advisories remain in effect. Heavy to excessive rainfall today could bring areas of flooding to parts of the northern High Plains and Midwest into the Ohio Valley. Flood Watches remain in effect. Read More >

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Fair

91°F

33°C

Humidity 41%
Wind Speed NW 5 mph
Barometer 29.83 in (1009.5 mb)
Dewpoint 64°F (18°C)
Visibility 10.00 mi
Heat Index93°F (34°C)
Last update 20 Sep 5:53 pm CDT
Extended Forecast for

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

  • Tonight

    Tonight: A chance of showers and thunderstorms before 1am, then showers likely and possibly a thunderstorm between 1am and 3am, then a chance of showers and thunderstorms after 3am. Mostly cloudy, with a low around 66. Northwest wind 5 to 7 mph becoming north after midnight. Chance of precipitation is 60%.

    Low: 66 °F

    Chance
    T-storms then
    Showers
    Likely

  • Monday

    Monday: A chance of showers before 11am, then a slight chance of showers and thunderstorms after 5pm. Cloudy, then gradually becoming mostly sunny, with a high near 76. North wind 5 to 8 mph. Chance of precipitation is 30%.

    High: 76 °F

    Chance
    Showers then
    Mostly Cloudy

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 60. Northeast wind 5 to 8 mph.

    Low: 60 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: Partly sunny, with a high near 73. North wind 7 to 10 mph.

    High: 73 °F

    Partly Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 53. Northeast wind 6 to 10 mph.

    Low: 53 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 75.

    High: 75 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 52.

    Low: 52 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny, with a high near 77.

    High: 77 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 54.

    Low: 54 °F

    Mostly Cloudy

Detailed Forecast

Tonight
A chance of showers and thunderstorms before 1am, then showers likely and possibly a thunderstorm between 1am and 3am, then a chance of showers and thunderstorms after 3am. Mostly cloudy, with a low around 66. Northwest wind 5 to 7 mph becoming north after midnight. Chance of precipitation is 60%.
Monday
A chance of showers before 11am, then a slight chance of showers and thunderstorms after 5pm. Cloudy, then gradually becoming mostly sunny, with a high near 76. North wind 5 to 8 mph. Chance of precipitation is 30%.
Monday Night
Mostly cloudy, with a low around 60. Northeast wind 5 to 8 mph.
Tuesday
Partly sunny, with a high near 73. North wind 7 to 10 mph.
Tuesday Night
Partly cloudy, with a low around 53. Northeast wind 6 to 10 mph.
Wednesday
Mostly sunny, with a high near 75.
Wednesday Night
Mostly clear, with a low around 52.
Thursday
Mostly sunny, with a high near 77.
Thursday Night
Mostly cloudy, with a low around 54.
Friday
Partly sunny, with a high near 78.
Friday Night
A 20 percent chance of showers. Mostly cloudy, with a low around 56.
Saturday
A 20 percent chance of showers. Mostly cloudy, with a high near 80.
Saturday Night
Mostly cloudy, with a low around 57.
Sunday
Mostly sunny, with a high near 85.
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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:
5:31 pm CDT Sep 20, 2026
Forecast Valid:
6pm CDT Sep 20, 2026-6pm CDT Sep 27, 2026
 
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Additional Resources

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation