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 S 5 mph
Barometer 30.05 in
Dewpoint N/A
Visibility 10.00 mi
Last update 2 Jul 11:35 pm CDT
Extended Forecast for

Alton IL

Extreme Heat Warning July 2, 11:50pm until July 4, 08:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning July 2, 11:50pm until July 4, 08:00pm

    NOW until 8:00pm Sat

    Extreme Heat Warning

  • Tonight

    Low: 77 °F

    Mostly Clear

  • Friday

    Friday: A 20 percent chance of showers and thunderstorms after 3pm. Sunny, with a high near 95. Heat index values as high as 104. Calm wind becoming south 5 to 8 mph in the morning.

    High: 95 °F

    Sunny then
    Slight Chance
    T-storms

  • Friday Night

    Friday Night: A 20 percent chance of showers and thunderstorms before 10pm. Partly cloudy, with a low around 75. South wind 5 to 7 mph becoming calm in the evening.

    Low: 75 °F

    Slight Chance
    T-storms then
    Mostly Clear

  • Independence Day

    Independence Day: A 40 percent chance of showers and thunderstorms, mainly after 1pm. Mostly sunny, with a high near 93. Heat index values as high as 102. Light and variable wind becoming southwest around 6 mph in the morning.

    High: 93 °F

    Chance
    T-storms

  • Saturday Night

    Saturday Night: A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74. South wind around 5 mph becoming calm in the evening.

    Low: 74 °F

    Chance
    T-storms

  • Sunday

    Sunday: A 30 percent chance of showers and thunderstorms, mainly before 1pm. Mostly sunny, with a high near 91.

    High: 91 °F

    Chance
    T-storms

  • Sunday Night

    Sunday Night: A slight chance of showers and thunderstorms. Partly cloudy, with a low around 72. Chance of precipitation is 20%.

    Low: 72 °F

    Slight Chance
    T-storms

  • Monday

    Monday: A slight chance of showers, with thunderstorms also possible after 1pm. Mostly sunny, with a high near 89. Chance of precipitation is 20%.

    High: 89 °F

    Slight Chance
    Showers then
    Slight Chance
    T-storms

Detailed Forecast

Tonight
Mostly clear, with a low around 77. South wind around 6 mph becoming calm after midnight.
Friday
A 20 percent chance of showers and thunderstorms after 3pm. Sunny, with a high near 95. Heat index values as high as 104. Calm wind becoming south 5 to 8 mph in the morning.
Friday Night
A 20 percent chance of showers and thunderstorms before 10pm. Partly cloudy, with a low around 75. South wind 5 to 7 mph becoming calm in the evening.
Independence Day
A 40 percent chance of showers and thunderstorms, mainly after 1pm. Mostly sunny, with a high near 93. Heat index values as high as 102. Light and variable wind becoming southwest around 6 mph in the morning.
Saturday Night
A 50 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74. South wind around 5 mph becoming calm in the evening.
Sunday
A 30 percent chance of showers and thunderstorms, mainly before 1pm. Mostly sunny, with a high near 91.
Sunday Night
A slight chance of showers and thunderstorms. Partly cloudy, with a low around 72. Chance of precipitation is 20%.
Monday
A slight chance of showers, with thunderstorms also possible after 1pm. Mostly sunny, with a high near 89. Chance of precipitation is 20%.
Monday Night
A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 70.
Tuesday
A slight chance of showers, then a chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 89. Chance of precipitation is 30%.
Tuesday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 71.
Wednesday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 90.
Wednesday Night
A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 71.
Thursday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 91.
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ABOUT THIS FORECAST

 
Point Forecast:
Alton IL
 38.91°N 90.16°W (Elev. 505 ft)
Last Update:
10:16 pm CDT Jul 2, 2026
Forecast Valid:
11pm CDT Jul 2, 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