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

74°F

23°C

Humidity 57%
Wind Speed Calm
Barometer 29.88 in (1011.3 mb)
Dewpoint 58°F (14°C)
Visibility 10.00 mi
Last update 13 Oct 12:53 am CDT
Extended Forecast for

Granite City IL

  • Overnight

    Overnight: Clear, with a low around 70. Southwest wind around 7 mph.

    Low: 70 °F

    Clear

  • Tuesday

    Tuesday: Sunny and hot, with a high near 98. Heat index values as high as 102. Southwest wind 6 to 9 mph.

    High: 98 °F

    Hot

  • Tuesday Night

    Tuesday Night: A 30 percent chance of showers and thunderstorms, mainly after 3am. Increasing clouds, with a low around 74. South wind 5 to 8 mph.

    Low: 74 °F

    Mostly Clear
    then Chance
    T-storms

  • Wednesday

    Wednesday: Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 83. Calm wind becoming northwest around 6 mph. Chance of precipitation is 100%.

    High: 83 °F

    Heavy Rain

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 68. Light and variable wind. Chance of precipitation is 60%.

    Low: 68 °F

    Showers
    Likely

  • Thursday

    Thursday: Showers and possibly a thunderstorm. High near 84. Chance of precipitation is 90%.

    High: 84 °F

    Showers

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 1am, then a slight chance of showers. Mostly cloudy, with a low around 55. Chance of precipitation is 30%.

    Low: 55 °F

    Chance
    Showers

  • Friday

    Friday: Partly sunny, with a high near 66. Breezy.

    High: 66 °F

    Partly Sunny
    and Breezy

  • Friday Night

    Friday Night: Mostly clear, with a low around 42.

    Low: 42 °F

    Mostly Clear

Detailed Forecast

Overnight
Clear, with a low around 70. Southwest wind around 7 mph.
Tuesday
Sunny and hot, with a high near 98. Heat index values as high as 102. Southwest wind 6 to 9 mph.
Tuesday Night
A 30 percent chance of showers and thunderstorms, mainly after 3am. Increasing clouds, with a low around 74. South wind 5 to 8 mph.
Wednesday
Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. High near 83. Calm wind becoming northwest around 6 mph. Chance of precipitation is 100%.
Wednesday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 68. Light and variable wind. Chance of precipitation is 60%.
Thursday
Showers and possibly a thunderstorm. High near 84. Chance of precipitation is 90%.
Thursday Night
A chance of showers and thunderstorms before 1am, then a slight chance of showers. Mostly cloudy, with a low around 55. Chance of precipitation is 30%.
Friday
Partly sunny, with a high near 66. Breezy.
Friday Night
Mostly clear, with a low around 42.
Saturday
Sunny, with a high near 65.
Saturday Night
Mostly clear, with a low around 41.
Sunday
Sunny, with a high near 72.
Sunday Night
Partly cloudy, with a low around 49.
Monday
Mostly sunny, with a high near 78.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Granite City IL
 38.71°N 90.14°W (Elev. 410 ft)
Last Update:
10:21 pm CDT Oct 12, 2026
Forecast Valid:
1am CDT Oct 13, 2026-6pm CDT Oct 19, 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