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.

A Few Clouds

81°F

27°C

Humidity 84%
Wind Speed Vrbl 6 mph
Barometer 30.04 in
Dewpoint 75°F (24°C)
Visibility 10.00 mi
Heat Index87°F (31°C)
Last update 15 Jul 8:50 am CDT
Extended Forecast for

Alton IL

  • Today

    Today: A 30 percent chance of showers and thunderstorms, mainly after 3pm. Mostly cloudy, with a high near 87. South wind around 6 mph.

    High: 87 °F

    Mostly Cloudy
    then Chance
    T-storms

  • Tonight

    Tonight: A 20 percent chance of showers and thunderstorms before 8pm. Mostly cloudy, with a low around 72. South wind around 5 mph becoming calm in the evening.

    Low: 72 °F

    Slight Chance
    T-storms then
    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 94. Heat index values as high as 100. Calm wind becoming southwest around 6 mph in the morning.

    High: 94 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 75. South wind around 6 mph.

    Low: 75 °F

    Slight Chance
    T-storms

  • Thursday

    Thursday: A 50 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 88. Northwest wind 5 to 7 mph.

    High: 88 °F

    Mostly Sunny
    then Chance
    T-storms

  • Thursday Night

    Thursday Night: A 40 percent chance of showers and thunderstorms, mainly before 1am. Mostly cloudy, with a low around 71.

    Low: 71 °F

    Chance
    T-storms

  • Friday

    Friday: A 30 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 85.

    High: 85 °F

    Mostly Cloudy
    then Chance
    T-storms

  • Friday Night

    Friday Night: A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 73.

    Low: 73 °F

    Slight Chance
    T-storms

  • Saturday

    Saturday: A 40 percent chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 92.

    High: 92 °F

    Chance
    T-storms

Detailed Forecast

Today
A 30 percent chance of showers and thunderstorms, mainly after 3pm. Mostly cloudy, with a high near 87. South wind around 6 mph.
Tonight
A 20 percent chance of showers and thunderstorms before 8pm. Mostly cloudy, with a low around 72. South wind around 5 mph becoming calm in the evening.
Wednesday
Mostly sunny, with a high near 94. Heat index values as high as 100. Calm wind becoming southwest around 6 mph in the morning.
Wednesday Night
A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 75. South wind around 6 mph.
Thursday
A 50 percent chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 88. Northwest wind 5 to 7 mph.
Thursday Night
A 40 percent chance of showers and thunderstorms, mainly before 1am. Mostly cloudy, with a low around 71.
Friday
A 30 percent chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 85.
Friday Night
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 73.
Saturday
A 40 percent chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 92.
Saturday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 75.
Sunday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 92.
Sunday Night
A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74.
Monday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 93.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Alton IL
 38.91°N 90.16°W (Elev. 505 ft)
Last Update:
6:06 am CDT Jul 15, 2025
Forecast Valid:
9am CDT Jul 15, 2025-6pm CDT Jul 21, 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