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.

Overcast

77°F

25°C

Humidity 74%
Wind Speed W 6 mph
Barometer 30.03 in (1016.6 mb)
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Heat Index79°F (26°C)
Last update 14 Oct 3:53 pm CDT
Extended Forecast for

Collinsville IL

  • This Afternoon

    This Afternoon: A 20 percent chance of showers. Cloudy, with a high near 76. North wind around 5 mph.

    High: 76 °F

    Slight Chance
    Showers

  • Tonight

    Tonight: A 30 percent chance of showers and thunderstorms, mainly after 4am. Cloudy, with a low around 67. Light and variable wind.

    Low: 67 °F

    Cloudy then
    Chance
    Showers

  • Thursday

    Thursday: Showers and possibly a thunderstorm, mainly before noon, then a chance of showers and thunderstorms after noon. High near 83. East wind 5 to 9 mph becoming southwest in the afternoon. Chance of precipitation is 80%.

    High: 83 °F

    Showers then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 50. Northwest wind 8 to 17 mph, with gusts as high as 28 mph. Chance of precipitation is 50%.

    Low: 50 °F

    Chance
    Showers

  • Friday

    Friday: Mostly cloudy, with a high near 57. Breezy, with a northwest wind 18 to 21 mph, with gusts as high as 31 mph.

    High: 57 °F

    Mostly Cloudy
    and Breezy

  • Friday Night

    Friday Night: Partly cloudy, with a low around 41.

    Low: 41 °F

    Partly Cloudy

  • Saturday

    Saturday: Sunny, with a high near 61.

    High: 61 °F

    Sunny

  • Saturday Night

    Saturday Night: Clear, with a low around 39.

    Low: 39 °F

    Clear

  • Sunday

    Sunday: Sunny, with a high near 67.

    High: 67 °F

    Sunny

Detailed Forecast

This Afternoon
A 20 percent chance of showers. Cloudy, with a high near 76. North wind around 5 mph.
Tonight
A 30 percent chance of showers and thunderstorms, mainly after 4am. Cloudy, with a low around 67. Light and variable wind.
Thursday
Showers and possibly a thunderstorm, mainly before noon, then a chance of showers and thunderstorms after noon. High near 83. East wind 5 to 9 mph becoming southwest in the afternoon. Chance of precipitation is 80%.
Thursday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 50. Northwest wind 8 to 17 mph, with gusts as high as 28 mph. Chance of precipitation is 50%.
Friday
Mostly cloudy, with a high near 57. Breezy, with a northwest wind 18 to 21 mph, with gusts as high as 31 mph.
Friday Night
Partly cloudy, with a low around 41.
Saturday
Sunny, with a high near 61.
Saturday Night
Clear, with a low around 39.
Sunday
Sunny, with a high near 67.
Sunday Night
Mostly clear, with a low around 43.
Monday
Mostly sunny, with a high near 73.
Monday Night
Partly cloudy, with a low around 47.
Tuesday
Mostly sunny, with a high near 75.
Tuesday Night
Mostly clear, with a low around 52.
Wednesday
Sunny, with a high near 80.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Collinsville IL
 38.68°N 90°W (Elev. 499 ft)
Last Update:
2:06 pm CDT Oct 14, 2026
Forecast Valid:
4pm CDT Oct 14, 2026-6pm CDT Oct 21, 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