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.

A Few Clouds

93°F

34°C

Humidity 42%
Wind Speed SW 7 mph
Barometer 29.87 in (1011.1 mb)
Dewpoint 67°F (19°C)
Visibility 10.00 mi
Heat Index96°F (36°C)
Last update 13 Oct 4:53 pm CDT
Extended Forecast for

Collinsville IL

  • Tonight

    Tonight: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 5am. Increasing clouds, with a low around 72. South wind 5 to 9 mph. Chance of precipitation is 60%.

    Low: 72 °F

    Mostly Clear
    then Showers
    Likely

  • Wednesday

    Wednesday: Showers and possibly a thunderstorm, mainly before 1pm, then a chance of showers and thunderstorms after 1pm. Patchy fog between 8am and 2pm. High near 78. Light and variable wind becoming west around 5 mph in the afternoon. Chance of precipitation is 90%.

    High: 78 °F

    Showers and
    Patchy Fog
    then Showers
    Likely and
    Patchy Fog

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms before 3am, then showers likely between 3am and 4am, then showers likely and possibly a thunderstorm after 4am. Mostly cloudy, with a low around 68. Light northeast wind. Chance of precipitation is 70%.

    Low: 68 °F

    Chance
    T-storms then
    Showers
    Likely

  • Thursday

    Thursday: Showers and possibly a thunderstorm. High near 83. Southeast wind 5 to 9 mph becoming southwest in the afternoon. Chance of precipitation is 90%.

    High: 83 °F

    Showers

  • Thursday Night

    Thursday Night: A 40 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 51. Northwest wind 8 to 18 mph, with gusts as high as 28 mph.

    Low: 51 °F

    Chance
    T-storms then
    Chance
    Showers

  • Friday

    Friday: Mostly sunny, with a high near 61. Breezy.

    High: 61 °F

    Mostly Sunny
    and Breezy

  • Friday Night

    Friday Night: Mostly clear, with a low around 38.

    Low: 38 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny, with a high near 62.

    High: 62 °F

    Sunny

  • Saturday Night

    Saturday Night: Clear, with a low around 39.

    Low: 39 °F

    Clear

Detailed Forecast

Tonight
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 5am. Increasing clouds, with a low around 72. South wind 5 to 9 mph. Chance of precipitation is 60%.
Wednesday
Showers and possibly a thunderstorm, mainly before 1pm, then a chance of showers and thunderstorms after 1pm. Patchy fog between 8am and 2pm. High near 78. Light and variable wind becoming west around 5 mph in the afternoon. Chance of precipitation is 90%.
Wednesday Night
A chance of showers and thunderstorms before 3am, then showers likely between 3am and 4am, then showers likely and possibly a thunderstorm after 4am. Mostly cloudy, with a low around 68. Light northeast wind. Chance of precipitation is 70%.
Thursday
Showers and possibly a thunderstorm. High near 83. Southeast wind 5 to 9 mph becoming southwest in the afternoon. Chance of precipitation is 90%.
Thursday Night
A 40 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 51. Northwest wind 8 to 18 mph, with gusts as high as 28 mph.
Friday
Mostly sunny, with a high near 61. Breezy.
Friday Night
Mostly clear, with a low around 38.
Saturday
Sunny, with a high near 62.
Saturday Night
Clear, with a low around 39.
Sunday
Sunny, with a high near 70.
Sunday Night
Partly cloudy, with a low around 47.
Monday
Mostly sunny, with a high near 74.
Monday Night
Partly cloudy, with a low around 51.
Tuesday
Mostly sunny, with a high near 79.
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ABOUT THIS FORECAST

 
Point Forecast:
Collinsville IL
 38.68°N 90°W (Elev. 499 ft)
Last Update:
3:01 pm CDT Oct 13, 2026
Forecast Valid:
5pm CDT Oct 13, 2026-6pm CDT Oct 20, 2026
 
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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