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

N/A

Humidity NA
Wind Speed Calm
Barometer 30.08 in
Dewpoint N/A
Visibility 10.00 mi
Last update 3 Jul 5:55 am CDT
Extended Forecast for

Alton IL

Extreme Heat Warning July 3, 06:15am until July 4, 08:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning July 3, 06:15am until July 4, 08:00pm

    NOW until 8:00pm Sat

    Extreme Heat Warning

  • Today

    High: 95 °F

    Sunny then
    Slight Chance
    T-storms

  • Tonight

    Tonight: Partly cloudy, with a low around 75. South wind 5 to 7 mph becoming calm in the evening.

    Low: 75 °F

    Partly Cloudy

  • Independence Day

    Independence Day: A 20 percent chance of showers and thunderstorms after 3pm. Mostly sunny, with a high near 93. Heat index values as high as 103. Calm wind becoming southwest 5 to 7 mph in the morning.

    High: 93 °F

    Sunny then
    Slight Chance
    T-storms

  • Saturday Night

    Saturday Night: A slight chance of showers and thunderstorms before 10pm, then a chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 73. South wind around 5 mph becoming calm in the evening. Chance of precipitation is 50%.

    Low: 73 °F

    Slight Chance
    T-storms then
    Chance
    T-storms

  • Sunday

    Sunday: A 40 percent chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 90. Calm wind becoming northwest around 6 mph in the morning.

    High: 90 °F

    Chance
    T-storms

  • Sunday Night

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

    Low: 71 °F

    Chance
    T-storms

  • Monday

    Monday: A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 88.

    High: 88 °F

    Slight Chance
    T-storms

  • Monday Night

    Monday Night: Partly cloudy, with a low around 70.

    Low: 70 °F

    Partly Cloudy

Detailed Forecast

Today
A 20 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 95. Heat index values as high as 103. Calm wind becoming south 5 to 8 mph in the morning.
Tonight
Partly cloudy, with a low around 75. South wind 5 to 7 mph becoming calm in the evening.
Independence Day
A 20 percent chance of showers and thunderstorms after 3pm. Mostly sunny, with a high near 93. Heat index values as high as 103. Calm wind becoming southwest 5 to 7 mph in the morning.
Saturday Night
A slight chance of showers and thunderstorms before 10pm, then a chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 73. South wind around 5 mph becoming calm in the evening. Chance of precipitation is 50%.
Sunday
A 40 percent chance of showers and thunderstorms, mainly after 1pm. Partly sunny, with a high near 90. Calm wind becoming northwest around 6 mph in the morning.
Sunday Night
A 40 percent chance of showers and thunderstorms, mainly before 1am. Partly cloudy, with a low around 71.
Monday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 88.
Monday Night
Partly cloudy, with a low around 70.
Tuesday
Mostly sunny, with a high near 88.
Tuesday Night
Mostly clear, with a low around 70.
Wednesday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 90.
Wednesday Night
Partly cloudy, with a low around 72.
Thursday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 91.
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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:
5:51 am CDT Jul 3, 2026
Forecast Valid:
6am CDT Jul 3, 2026-6pm CDT Jul 9, 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