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

Hazardous Weather Conditions

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Mostly Cloudy

72°F

22°C

Humidity 97%
Wind Speed Calm
Barometer 29.90 in (1012.1 mb)
Dewpoint 71°F (22°C)
Visibility 9.00 mi
Last update 27 Jun 12:53 am CDT
Extended Forecast for

Collinsville IL

Flood Watch June 27, 01:10am until June 27, 07:00am
Click here for hazard details and duration
Flood Watch
  •  
    Flood Watch June 27, 01:10am until June 27, 07:00am

    NOW until 7:00am Sat

    Flood Watch

  • Overnight

    Low: 69 °F

    Chance
    Showers and
    Patchy Fog

  • Saturday

    Saturday: A chance of showers and thunderstorms before noon, then a slight chance of showers and thunderstorms after 4pm. Patchy fog before 9am. Otherwise, mostly cloudy, with a high near 84. Calm wind becoming south 5 to 7 mph in the morning. Chance of precipitation is 30%.

    High: 84 °F

    Chance
    Showers and
    Patchy Fog
    then Slight
    Chance
    T-storms

  • Saturday Night

    Saturday Night: A 30 percent chance of showers and thunderstorms, mainly between midnight and 4am. Mostly cloudy, with a low around 73. Southeast wind around 6 mph.

    Low: 73 °F

    Chance
    T-storms

  • Sunday

    Sunday: Mostly cloudy, then gradually becoming sunny, with a high near 93. Heat index values as high as 109. South wind 7 to 11 mph.

    High: 93 °F

    Decreasing
    Clouds

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 76. South wind 6 to 9 mph.

    Low: 76 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 96.

    High: 96 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 77.

    Low: 77 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 96.

    High: 96 °F

    Sunny

Detailed Forecast

Overnight
A chance of showers and thunderstorms before 4am, then a slight chance of showers. Patchy fog after 4am. Otherwise, mostly cloudy, with a low around 69. Calm wind. Chance of precipitation is 30%.
Saturday
A chance of showers and thunderstorms before noon, then a slight chance of showers and thunderstorms after 4pm. Patchy fog before 9am. Otherwise, mostly cloudy, with a high near 84. Calm wind becoming south 5 to 7 mph in the morning. Chance of precipitation is 30%.
Saturday Night
A 30 percent chance of showers and thunderstorms, mainly between midnight and 4am. Mostly cloudy, with a low around 73. Southeast wind around 6 mph.
Sunday
Mostly cloudy, then gradually becoming sunny, with a high near 93. Heat index values as high as 109. South wind 7 to 11 mph.
Sunday Night
Mostly clear, with a low around 76. South wind 6 to 9 mph.
Monday
Sunny, with a high near 96.
Monday Night
Mostly clear, with a low around 77.
Tuesday
Sunny, with a high near 96.
Tuesday Night
Clear, with a low around 77.
Wednesday
Sunny, with a high near 96.
Wednesday Night
Mostly clear, with a low around 78.
Thursday
Sunny, with a high near 96.
Thursday Night
Mostly clear, with a low around 78.
Friday
A 40 percent chance of showers and thunderstorms. Sunny, with a high near 96.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Collinsville IL
 38.68°N 89.97°W (Elev. 502 ft)
Last Update:
10:31 pm CDT Jun 26, 2026
Forecast Valid:
1am CDT Jun 27, 2026-6pm CDT Jul 3, 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