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

52°F

11°C

Humidity 83%
Wind Speed Calm
Barometer 29.88 in (1011.6 mb)
Dewpoint 47°F (8°C)
Visibility 10.00 mi
Last update 21 Mar 3:53 am CDT
Extended Forecast for

Granite City IL

  • Overnight

    Overnight: Mostly clear, with a low around 51. Calm wind.

    Low: 51 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny, with a high near 89. Calm wind becoming south 5 to 7 mph in the morning.

    High: 89 °F

    Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 64. South wind 5 to 8 mph.

    Low: 64 °F

    Mostly Clear

  • Sunday

    Sunday: Increasing clouds, with a high near 89. South wind 8 to 16 mph becoming northwest in the afternoon. Winds could gust as high as 24 mph.

    High: 89 °F

    Increasing
    Clouds

  • Sunday Night

    Sunday Night: A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Partly cloudy, with a low around 39. Breezy, with a north wind 16 to 21 mph decreasing to 10 to 15 mph after midnight. Winds could gust as high as 32 mph. Chance of precipitation is 20%.

    Low: 39 °F

    Slight Chance
    T-storms and
    Breezy then
    Slight Chance
    Showers

  • Monday

    Monday: Mostly sunny, with a high near 58.

    High: 58 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 41.

    Low: 41 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: Partly sunny, with a high near 63.

    High: 63 °F

    Partly Sunny

  • Tuesday Night

    Tuesday Night: A 20 percent chance of showers after 1am. Mostly cloudy, with a low around 45.

    Low: 45 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

Detailed Forecast

Overnight
Mostly clear, with a low around 51. Calm wind.
Saturday
Sunny, with a high near 89. Calm wind becoming south 5 to 7 mph in the morning.
Saturday Night
Mostly clear, with a low around 64. South wind 5 to 8 mph.
Sunday
Increasing clouds, with a high near 89. South wind 8 to 16 mph becoming northwest in the afternoon. Winds could gust as high as 24 mph.
Sunday Night
A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Partly cloudy, with a low around 39. Breezy, with a north wind 16 to 21 mph decreasing to 10 to 15 mph after midnight. Winds could gust as high as 32 mph. Chance of precipitation is 20%.
Monday
Mostly sunny, with a high near 58.
Monday Night
Mostly cloudy, with a low around 41.
Tuesday
Partly sunny, with a high near 63.
Tuesday Night
A 20 percent chance of showers after 1am. Mostly cloudy, with a low around 45.
Wednesday
A 20 percent chance of showers and thunderstorms before 1pm. Partly sunny, with a high near 72.
Wednesday Night
A 20 percent chance of showers. Partly cloudy, with a low around 56.
Thursday
A 20 percent chance of showers. Mostly sunny, with a high near 82.
Thursday Night
A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 47.
Friday
A 30 percent chance of showers. Partly sunny, with a high near 58.
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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:
2:46 am CDT Mar 21, 2026
Forecast Valid:
3am CDT Mar 21, 2026-6pm CDT Mar 27, 2026
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation