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

St. Louis Regional Airport (KALN)

Lat: 38.89°NLon: 90.03°WElev: 518ft.

Partly Cloudy

77°F

25°C

Humidity 44%
Wind Speed NE 9 mph
Barometer 30.25 in
Dewpoint 54°F (12°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 2 Aug 3:50 pm CDT
Extended Forecast for

Alton ILSimilar City Names

  • Tonight

    Tonight: Partly cloudy, with a low around 56. Northeast wind 3 to 8 mph.

    Low: 56 °F

    Partly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 81. Northeast wind 5 to 7 mph.

    High: 81 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 64. Northeast wind around 6 mph becoming calm after midnight.

    Low: 64 °F

    Partly Cloudy

  • Monday

    Monday: A 20 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 81. East wind 3 to 5 mph.

    High: 81 °F

    Partly Sunny
    then Slight
    Chance
    T-storms

  • Monday Night

    Monday Night: Partly cloudy, with a low around 66. East wind around 6 mph becoming calm in the evening.

    Low: 66 °F

    Partly Cloudy

  • Tuesday

    Tuesday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 84.

    High: 84 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 68.

    Low: 68 °F

    Mostly Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 87.

    High: 87 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 69.

    Low: 69 °F

    Mostly Clear

Detailed Forecast

Tonight
Partly cloudy, with a low around 56. Northeast wind 3 to 8 mph.
Sunday
Mostly sunny, with a high near 81. Northeast wind 5 to 7 mph.
Sunday Night
Partly cloudy, with a low around 64. Northeast wind around 6 mph becoming calm after midnight.
Monday
A 20 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 81. East wind 3 to 5 mph.
Monday Night
Partly cloudy, with a low around 66. East wind around 6 mph becoming calm in the evening.
Tuesday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 84.
Tuesday Night
Mostly clear, with a low around 68.
Wednesday
Mostly sunny, with a high near 87.
Wednesday Night
Mostly clear, with a low around 69.
Thursday
Sunny, with a high near 88.
Thursday Night
Mostly clear, with a low around 71.
Friday
Sunny, with a high near 90.
Friday Night
Mostly clear, with a low around 72.
Saturday
Sunny, with a high near 92.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Alton ILSimilar City Names
 38.91°N 90.16°W (Elev. 505 ft)
Last Update:
4:16 pm CDT Aug 2, 2025
Forecast Valid:
4pm CDT Aug 2, 2025-6pm CDT Aug 9, 2025
 
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Additional Resources

Radar & Satellite Image

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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