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

81°F

27°C

Humidity 84%
Wind Speed S 12 mph
Barometer 29.99 in
Dewpoint 75°F (24°C)
Visibility 10.00 mi
Heat Index87°F (31°C)
Last update 21 Jun 7:50 am CDT
Extended Forecast for

Alton IL

Extreme Heat Warning June 21, 12:00pm until June 24, 09:00pm
Click here for hazard details and duration
Extreme Heat Warning

  • Today

    Today: Sunny, with a high near 96. Heat index values as high as 105. Southwest wind 11 to 15 mph, with gusts as high as 23 mph.

    High: 96 °F

    Sunny

  • Tonight

    Tonight: Clear, with a low around 77. South wind 8 to 13 mph, with gusts as high as 21 mph.

    Low: 77 °F

    Clear

  • Sunday

    Sunday: Sunny, with a high near 96. Heat index values as high as 100. Southwest wind 7 to 11 mph.

    High: 96 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 76. South wind 6 to 10 mph.

    Low: 76 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 95. Southwest wind 6 to 8 mph.

    High: 95 °F

    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 76.

    Low: 76 °F

    Partly Cloudy

  • Tuesday

    Tuesday: A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 92.

    High: 92 °F

    Slight Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 75.

    Low: 75 °F

    Partly Cloudy

  • Wednesday

    Wednesday: A 20 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 94.

    High: 94 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

Detailed Forecast

Today
Sunny, with a high near 96. Heat index values as high as 105. Southwest wind 11 to 15 mph, with gusts as high as 23 mph.
Tonight
Clear, with a low around 77. South wind 8 to 13 mph, with gusts as high as 21 mph.
Sunday
Sunny, with a high near 96. Heat index values as high as 100. Southwest wind 7 to 11 mph.
Sunday Night
Mostly clear, with a low around 76. South wind 6 to 10 mph.
Monday
Sunny, with a high near 95. Southwest wind 6 to 8 mph.
Monday Night
Partly cloudy, with a low around 76.
Tuesday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 92.
Tuesday Night
Partly cloudy, with a low around 75.
Wednesday
A 20 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 94.
Wednesday Night
Mostly clear, with a low around 76.
Thursday
A 20 percent chance of showers and thunderstorms. Sunny, with a high near 93.
Thursday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74.
Friday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 90.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Alton IL
 38.93°N 90.16°W (Elev. 505 ft)
Last Update:
5:37 am CDT Jun 21, 2025
Forecast Valid:
8am CDT Jun 21, 2025-6pm CDT Jun 27, 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