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

80°F

27°C

Humidity 34%
Wind Speed SW 10 G 23 mph
Barometer 30.04 in (1017.0 mb)
Dewpoint 49°F (9°C)
Visibility 10.00 mi
Heat Index79°F (26°C)
Last update 21 Apr 1:53 pm CDT
Extended Forecast for

Granite City IL

  • This Afternoon

    This Afternoon: Sunny, with a high near 81. Southwest wind around 15 mph, with gusts as high as 23 mph.

    High: 81 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 59. Southwest wind 7 to 11 mph, with gusts as high as 21 mph.

    Low: 59 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 80. Southwest wind 6 to 9 mph.

    High: 80 °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: Sunny, with a high near 83. South wind 6 to 11 mph increasing to 12 to 17 mph in the afternoon. Winds could gust as high as 28 mph.

    High: 83 °F

    Sunny

  • Thursday Night

    Thursday Night: Showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 64. Chance of precipitation is 60%.

    Low: 64 °F

    Partly Cloudy
    then Showers
    Likely

  • Friday

    Friday: Showers and possibly a thunderstorm. High near 79. Chance of precipitation is 80%.

    High: 79 °F

    Showers

  • Friday Night

    Friday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 56. Chance of precipitation is 40%.

    Low: 56 °F

    Chance
    T-storms

  • Saturday

    Saturday: Mostly sunny, with a high near 77.

    High: 77 °F

    Mostly Sunny

Detailed Forecast

This Afternoon
Sunny, with a high near 81. Southwest wind around 15 mph, with gusts as high as 23 mph.
Tonight
Mostly clear, with a low around 59. Southwest wind 7 to 11 mph, with gusts as high as 21 mph.
Wednesday
Sunny, with a high near 80. Southwest wind 6 to 9 mph.
Wednesday Night
Mostly clear, with a low around 59. South wind around 6 mph.
Thursday
Sunny, with a high near 83. South wind 6 to 11 mph increasing to 12 to 17 mph in the afternoon. Winds could gust as high as 28 mph.
Thursday Night
Showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 64. Chance of precipitation is 60%.
Friday
Showers and possibly a thunderstorm. High near 79. Chance of precipitation is 80%.
Friday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 56. Chance of precipitation is 40%.
Saturday
Mostly sunny, with a high near 77.
Saturday Night
A 20 percent chance of showers after 1am. Partly cloudy, with a low around 54.
Sunday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 77.
Sunday Night
Showers and thunderstorms likely. Mostly cloudy, with a low around 60. Chance of precipitation is 60%.
Monday
Showers likely and possibly a thunderstorm. Partly sunny, with a high near 78. Chance of precipitation is 60%.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Granite City IL
 38.73°N 90.11°W (Elev. 417 ft)
Last Update:
1:25 pm CDT Apr 21, 2026
Forecast Valid:
2pm 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