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

57°F

14°C

Humidity 62%
Wind Speed Calm
Barometer 30.11 in (1019.4 mb)
Dewpoint 44°F (7°C)
Visibility 10.00 mi
Last update 21 Apr 2:53 am CDT
Extended Forecast for

Granite City IL

  • Overnight

    Overnight: Mostly clear, with a low around 50. South wind around 7 mph.

    Low: 50 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 81. Southwest wind 6 to 16 mph, with gusts as high as 26 mph.

    High: 81 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 58. Southwest wind 7 to 13 mph, with gusts as high as 20 mph.

    Low: 58 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 79. West wind 6 to 9 mph.

    High: 79 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 59. South wind around 6 mph.

    Low: 59 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny, with a high near 83.

    High: 83 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 63. Chance of precipitation is 70%.

    Low: 63 °F

    Mostly Cloudy
    then Showers
    Likely

  • Friday

    Friday: Showers and possibly a thunderstorm. High near 77. Chance of precipitation is 80%.

    High: 77 °F

    Showers

  • Friday Night

    Friday Night: A chance of showers and thunderstorms. Partly cloudy, with a low around 56. Chance of precipitation is 30%.

    Low: 56 °F

    Chance
    T-storms

Detailed Forecast

Overnight
Mostly clear, with a low around 50. South wind around 7 mph.
Tuesday
Mostly sunny, with a high near 81. Southwest wind 6 to 16 mph, with gusts as high as 26 mph.
Tuesday Night
Mostly clear, with a low around 58. Southwest wind 7 to 13 mph, with gusts as high as 20 mph.
Wednesday
Sunny, with a high near 79. West wind 6 to 9 mph.
Wednesday Night
Mostly clear, with a low around 59. South wind around 6 mph.
Thursday
Mostly sunny, with a high near 83.
Thursday Night
Showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 63. Chance of precipitation is 70%.
Friday
Showers and possibly a thunderstorm. High near 77. Chance of precipitation is 80%.
Friday Night
A chance of showers and thunderstorms. Partly cloudy, with a low around 56. Chance of precipitation is 30%.
Saturday
A 20 percent chance of showers after 1pm. Mostly sunny, with a high near 75.
Saturday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 53.
Sunday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 74.
Sunday Night
Showers and thunderstorms likely. Mostly cloudy, with a low around 59. Chance of precipitation is 60%.
Monday
Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 75. Chance of precipitation is 60%.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Granite City IL
 38.73°N 90.11°W (Elev. 417 ft)
Last Update:
3:01 am CDT Apr 21, 2026
Forecast Valid:
3am CDT Apr 21, 2026-6pm CDT Apr 27, 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