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

39°F

4°C

Humidity 65%
Wind Speed NE 9 mph
Barometer 30.10 in (1019.2 mb)
Dewpoint 28°F (-2°C)
Visibility 10.00 mi
Wind Chill33°F (1°C)
Last update 14 Mar 4:53 am CDT
Extended Forecast for

Collinsville IL

  • Today

    Today: Mostly sunny, with a high near 62. East wind 7 to 15 mph becoming southeast in the afternoon. Winds could gust as high as 22 mph.

    High: 62 °F

    Mostly Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 55. South wind 10 to 17 mph, with gusts as high as 26 mph.

    Low: 55 °F

    Partly Cloudy

  • Sunday

    Sunday: A chance of rain and thunderstorms, then rain after 1pm. High near 67. Breezy, with a south wind 22 to 25 mph, with gusts as high as 40 mph. Chance of precipitation is 90%.

    High: 67 °F

    Breezy.
    Chance Rain
    then Rain

  • Sunday Night

    Sunday Night: Rain before 10pm, then rain and snow between 10pm and 1am, then a chance of snow after 1am. Low around 22. Breezy, with a southwest wind 22 to 29 mph becoming northwest in the evening. Winds could gust as high as 41 mph. Chance of precipitation is 90%. New snow accumulation of less than a half inch possible.

    Low: 22 °F

    Rain/Snow and
    Breezy

  • Monday

    Monday: A 30 percent chance of snow before 1pm. Mostly cloudy, with a high near 28. Blustery, with a northwest wind 23 to 26 mph, with gusts as high as 40 mph.

    High: 28 °F

    Chance Snow
    and Blustery

  • Monday Night

    Monday Night: Partly cloudy, with a low around 13. Blustery.

    Low: 13 °F

    Mostly Cloudy
    and Blustery
    then Mostly
    Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 36.

    High: 36 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: A slight chance of snow before 1am, then a chance of rain and snow. Mostly cloudy, with a low around 30. Chance of precipitation is 30%.

    Low: 30 °F

    Slight Chance
    Snow then
    Chance
    Rain/Snow

  • Wednesday

    Wednesday: Partly sunny, with a high near 63.

    High: 63 °F

    Partly Sunny

Detailed Forecast

Today
Mostly sunny, with a high near 62. East wind 7 to 15 mph becoming southeast in the afternoon. Winds could gust as high as 22 mph.
Tonight
Partly cloudy, with a low around 55. South wind 10 to 17 mph, with gusts as high as 26 mph.
Sunday
A chance of rain and thunderstorms, then rain after 1pm. High near 67. Breezy, with a south wind 22 to 25 mph, with gusts as high as 40 mph. Chance of precipitation is 90%.
Sunday Night
Rain before 10pm, then rain and snow between 10pm and 1am, then a chance of snow after 1am. Low around 22. Breezy, with a southwest wind 22 to 29 mph becoming northwest in the evening. Winds could gust as high as 41 mph. Chance of precipitation is 90%. New snow accumulation of less than a half inch possible.
Monday
A 30 percent chance of snow before 1pm. Mostly cloudy, with a high near 28. Blustery, with a northwest wind 23 to 26 mph, with gusts as high as 40 mph.
Monday Night
Partly cloudy, with a low around 13. Blustery.
Tuesday
Mostly sunny, with a high near 36.
Tuesday Night
A slight chance of snow before 1am, then a chance of rain and snow. Mostly cloudy, with a low around 30. Chance of precipitation is 30%.
Wednesday
Partly sunny, with a high near 63.
Wednesday Night
Mostly clear, with a low around 40.
Thursday
Sunny, with a high near 70.
Thursday Night
Partly cloudy, with a low around 48.
Friday
Sunny, with a high near 70.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Collinsville IL
 38.68°N 89.97°W (Elev. 502 ft)
Last Update:
4:41 am CDT Mar 14, 2026
Forecast Valid:
5am CDT Mar 14, 2026-6pm CDT Mar 20, 2026
 
Forecast Discussion
 
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Additional Resources

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Chance of Precipitation