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.

Fair

66°F

19°C

Humidity 73%
Wind Speed NW 3 mph
Barometer 29.96 in
Dewpoint 57°F (14°C)
Visibility 10.00 mi
Last update 22 Apr 8:50 pm CDT
Extended Forecast for

Alton ILSimilar City Names

  • Tonight

    Tonight: Mostly clear, with a low around 59. South wind around 5 mph.

    Low: 59 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 82. South wind 7 to 17 mph, with gusts as high as 28 mph.

    High: 82 °F

    Sunny

  • Thursday Night

    Thursday Night: Showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 62. South wind 10 to 15 mph, with gusts as high as 23 mph. Chance of precipitation is 70%.

    Low: 62 °F

    Partly Cloudy
    then Showers
    Likely

  • Friday

    Friday: Showers and possibly a thunderstorm. High near 74. South wind around 10 mph becoming west in the afternoon. Chance of precipitation is 80%.

    High: 74 °F

    Showers

  • Friday Night

    Friday Night: A chance of showers and thunderstorms before 10pm, then a chance of showers between 10pm and 1am. Partly cloudy, with a low around 53. North wind around 7 mph. Chance of precipitation is 30%.

    Low: 53 °F

    Chance
    Showers

  • Saturday

    Saturday: Sunny, with a high near 76.

    High: 76 °F

    Sunny

  • Saturday Night

    Saturday Night: A 20 percent chance of showers before 1am. Partly cloudy, with a low around 54.

    Low: 54 °F

    Slight Chance
    Showers

  • Sunday

    Sunday: A 20 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 74.

    High: 74 °F

    Partly Sunny
    then Slight
    Chance
    T-storms

  • Sunday Night

    Sunday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 62. Chance of precipitation is 60%.

    Low: 62 °F

    Showers
    Likely

Detailed Forecast

Tonight
Mostly clear, with a low around 59. South wind around 5 mph.
Thursday
Sunny, with a high near 82. South wind 7 to 17 mph, with gusts as high as 28 mph.
Thursday Night
Showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 62. South wind 10 to 15 mph, with gusts as high as 23 mph. Chance of precipitation is 70%.
Friday
Showers and possibly a thunderstorm. High near 74. South wind around 10 mph becoming west in the afternoon. Chance of precipitation is 80%.
Friday Night
A chance of showers and thunderstorms before 10pm, then a chance of showers between 10pm and 1am. Partly cloudy, with a low around 53. North wind around 7 mph. Chance of precipitation is 30%.
Saturday
Sunny, with a high near 76.
Saturday Night
A 20 percent chance of showers before 1am. Partly cloudy, with a low around 54.
Sunday
A 20 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 74.
Sunday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 62. Chance of precipitation is 60%.
Monday
Showers and possibly a thunderstorm. High near 78. Breezy. Chance of precipitation is 80%.
Monday Night
A 30 percent chance of showers. Partly cloudy, with a low around 52.
Tuesday
Mostly sunny, with a high near 71.
Tuesday Night
Partly cloudy, with a low around 51.
Wednesday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 69.
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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:
8:21 pm CDT Apr 22, 2026
Forecast Valid:
9pm CDT Apr 22, 2026-6pm CDT Apr 29, 2026
 
Forecast Discussion
 
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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