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

Hazardous Weather Conditions

Current conditions at

St. Louis Regional Airport (KALN)

Lat: 38.89°NLon: 90.03°WElev: 518ft.

Fair

70°F

21°C

Humidity 46%
Wind Speed S 16 G 22 mph
Barometer 29.93 in
Dewpoint 48°F (9°C)
Visibility 10.00 mi
Last update 15 May 10:50 am CDT
Extended Forecast for

Alton IL

  • Today

    Today: Mostly sunny, with a high near 83. South wind around 14 mph, with gusts as high as 22 mph.

    High: 83 °F

    Mostly Sunny

  • Tonight

    Tonight: A slight chance of showers between 3am and 4am, then a chance of showers and thunderstorms after 4am. Mostly cloudy, with a low around 65. South wind 8 to 11 mph. Chance of precipitation is 30%.

    Low: 65 °F

    Mostly Cloudy
    then Chance
    T-storms

  • Saturday

    Saturday: Showers and thunderstorms likely, mainly before 3pm. Partly sunny, with a high near 83. Southwest wind 7 to 9 mph. Chance of precipitation is 70%.

    High: 83 °F

    Showers
    Likely then
    Chance
    T-storms

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 64. South wind 7 to 9 mph.

    Low: 64 °F

    Partly Cloudy

  • Sunday

    Sunday: Sunny, with a high near 89. South wind 9 to 17 mph, with gusts as high as 28 mph.

    High: 89 °F

    Sunny

  • Sunday Night

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

    Low: 69 °F

    Mostly Clear

  • Monday

    Monday: A 50 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 89.

    High: 89 °F

    Mostly Sunny
    then Chance
    T-storms

  • Monday Night

    Monday Night: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 69.

    Low: 69 °F

    Chance
    T-storms

  • Tuesday

    Tuesday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Partly sunny, with a high near 86. Chance of precipitation is 70%.

    High: 86 °F

    Chance
    T-storms then
    Showers
    Likely

Detailed Forecast

Today
Mostly sunny, with a high near 83. South wind around 14 mph, with gusts as high as 22 mph.
Tonight
A slight chance of showers between 3am and 4am, then a chance of showers and thunderstorms after 4am. Mostly cloudy, with a low around 65. South wind 8 to 11 mph. Chance of precipitation is 30%.
Saturday
Showers and thunderstorms likely, mainly before 3pm. Partly sunny, with a high near 83. Southwest wind 7 to 9 mph. Chance of precipitation is 70%.
Saturday Night
Partly cloudy, with a low around 64. South wind 7 to 9 mph.
Sunday
Sunny, with a high near 89. South wind 9 to 17 mph, with gusts as high as 28 mph.
Sunday Night
Mostly clear, with a low around 69.
Monday
A 50 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 89.
Monday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 69.
Tuesday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Partly sunny, with a high near 86. Chance of precipitation is 70%.
Tuesday Night
Showers likely and possibly a thunderstorm before 1am, then a chance of showers. Mostly cloudy, with a low around 60. Chance of precipitation is 60%.
Wednesday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 75.
Wednesday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 55.
Thursday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 74.
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ABOUT THIS FORECAST

 
Point Forecast:
Alton IL
 38.91°N 90.16°W (Elev. 505 ft)
Last Update:
8:26 am CDT May 15, 2026
Forecast Valid:
11am CDT May 15, 2026-6pm CDT May 21, 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