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.

Mostly Cloudy

59°F

15°C

Humidity 77%
Wind Speed E 6 mph
Barometer 29.82 in
Dewpoint 52°F (11°C)
Visibility 10.00 mi
Last update 18 Nov 11:50 am CST
Extended Forecast for

Alton IL

  • This Afternoon

    This Afternoon: A 20 percent chance of rain and thunderstorms before 1pm. Mostly cloudy, with a high near 66. South wind around 7 mph becoming north.

    High: 66 °F

    Slight Chance
    T-storms

  • Tonight

    Tonight: Mostly cloudy, with a low around 44. North wind 3 to 6 mph.

    Low: 44 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Mostly cloudy, with a high near 59. Light and variable wind.

    High: 59 °F

    Mostly Cloudy

  • Wednesday Night

    Wednesday Night: A 30 percent chance of rain after midnight. Mostly cloudy, with a low around 47. Light and variable wind.

    Low: 47 °F

    Mostly Cloudy
    then Chance
    Rain

  • Thursday

    Thursday: Rain likely. Cloudy, with a high near 61. South wind 3 to 7 mph. Chance of precipitation is 70%.

    High: 61 °F

    Rain Likely

  • Thursday Night

    Thursday Night: Rain likely and possibly a thunderstorm. Cloudy, with a low around 49. Chance of precipitation is 70%.

    Low: 49 °F

    Rain Likely

  • Friday

    Friday: Rain likely. Mostly cloudy, with a high near 57. Chance of precipitation is 70%.

    High: 57 °F

    Rain Likely

  • Friday Night

    Friday Night: A 50 percent chance of rain, mainly before midnight. Mostly cloudy, with a low around 40.

    Low: 40 °F

    Chance Rain
    then Slight
    Chance Rain

  • Saturday

    Saturday: Mostly sunny, with a high near 56.

    High: 56 °F

    Mostly Sunny

Detailed Forecast

This Afternoon
A 20 percent chance of rain and thunderstorms before 1pm. Mostly cloudy, with a high near 66. South wind around 7 mph becoming north.
Tonight
Mostly cloudy, with a low around 44. North wind 3 to 6 mph.
Wednesday
Mostly cloudy, with a high near 59. Light and variable wind.
Wednesday Night
A 30 percent chance of rain after midnight. Mostly cloudy, with a low around 47. Light and variable wind.
Thursday
Rain likely. Cloudy, with a high near 61. South wind 3 to 7 mph. Chance of precipitation is 70%.
Thursday Night
Rain likely and possibly a thunderstorm. Cloudy, with a low around 49. Chance of precipitation is 70%.
Friday
Rain likely. Mostly cloudy, with a high near 57. Chance of precipitation is 70%.
Friday Night
A 50 percent chance of rain, mainly before midnight. Mostly cloudy, with a low around 40.
Saturday
Mostly sunny, with a high near 56.
Saturday Night
Mostly clear, with a low around 38.
Sunday
Sunny, with a high near 59.
Sunday Night
Partly cloudy, with a low around 41.
Monday
A 20 percent chance of rain. Partly sunny, with a high near 60.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Alton IL
 38.91°N 90.13°W (Elev. 499 ft)
Last Update:
7:26 am CST Nov 18, 2025
Forecast Valid:
12pm CST Nov 18, 2025-6pm CST Nov 24, 2025
 
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