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

32°F

0°C

Humidity 60%
Wind Speed NW 9 mph
Barometer 30.30 in
Dewpoint 19°F (-7°C)
Visibility 10.00 mi
Wind Chill24°F (-4°C)
Last update 21 Feb 8:50 pm CST
Extended Forecast for

Alton ILSimilar City Names

  • Tonight

    Tonight: Mostly clear, with a low around 22. Northwest wind 11 to 15 mph, with gusts as high as 25 mph.

    Low: 22 °F

    Mostly Clear

  • Sunday

    Sunday: Mostly sunny, with a high near 30. Blustery, with a northwest wind 16 to 22 mph, with gusts as high as 33 mph.

    High: 30 °F

    Mostly Sunny
    and Blustery

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 15. Northwest wind 14 to 16 mph, with gusts as high as 26 mph.

    Low: 15 °F

    Partly Cloudy

  • Monday

    Monday: Sunny, with a high near 33. Northwest wind 7 to 14 mph, with gusts as high as 22 mph.

    High: 33 °F

    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 20. Calm wind becoming south around 6 mph after midnight.

    Low: 20 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Partly sunny, with a high near 53.

    High: 53 °F

    Partly Sunny

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 40.

    Low: 40 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Partly sunny, with a high near 57.

    High: 57 °F

    Partly Sunny

  • Wednesday Night

    Wednesday Night: A 40 percent chance of rain, mainly after midnight. Mostly cloudy, with a low around 34.

    Low: 34 °F

    Chance Rain

Detailed Forecast

Tonight
Mostly clear, with a low around 22. Northwest wind 11 to 15 mph, with gusts as high as 25 mph.
Sunday
Mostly sunny, with a high near 30. Blustery, with a northwest wind 16 to 22 mph, with gusts as high as 33 mph.
Sunday Night
Partly cloudy, with a low around 15. Northwest wind 14 to 16 mph, with gusts as high as 26 mph.
Monday
Sunny, with a high near 33. Northwest wind 7 to 14 mph, with gusts as high as 22 mph.
Monday Night
Partly cloudy, with a low around 20. Calm wind becoming south around 6 mph after midnight.
Tuesday
Partly sunny, with a high near 53.
Tuesday Night
Mostly cloudy, with a low around 40.
Wednesday
Partly sunny, with a high near 57.
Wednesday Night
A 40 percent chance of rain, mainly after midnight. Mostly cloudy, with a low around 34.
Thursday
A 40 percent chance of rain. Mostly sunny, with a high near 49.
Thursday Night
Mostly clear, with a low around 30.
Friday
Sunny, with a high near 60.
Friday Night
Mostly clear, with a low around 38.
Saturday
Mostly sunny, with a high near 60.
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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 CST Feb 21, 2026
Forecast Valid:
9pm CST Feb 21, 2026-6pm CST Feb 28, 2026
 
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Additional Resources

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation