National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Tropical Storm Edouard to Impact the Northwest Gulf Coast; Heat Expands Eastward

Tropical Storm Edouard will bring tropical storm to hurricane conditions, heavy rainfall, flash and some river flooding, and storm surge to portions of Upper Texas and southwestern Louisiana coasts into Wednesday. Severe thunderstorms are possible in the Central Plains and Mid-Atlantic. Hot and humid conditions will expand from the Central Plains into the Ohio Valley and Mid-Atlantic. Read More >

Hazardous Weather Conditions

Current conditions at

St. Louis Regional Airport (KALN)

Lat: 38.89°NLon: 90.03°WElev: 518ft.

Fair

99°F

37°C

Humidity 35%
Wind Speed SW 7 mph
Barometer 29.99 in
Dewpoint 66°F (19°C)
Visibility 10.00 mi
Heat Index104°F (40°C)
Last update 1 Sep 3:50 pm CDT
Extended Forecast for

Alton IL

Heat Advisory September 1, 04:24pm until September 5, 08:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory September 1, 04:24pm until September 5, 08:00pm

    NOW until 8:00pm Sat

    Heat Advisory

  • Tonight

    Low: 77 °F

    Clear

  • Wednesday

    Wednesday: Sunny and hot, with a high near 98. Heat index values as high as 102. Southwest wind 5 to 8 mph.

    High: 98 °F

    Hot

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 79. South wind around 6 mph.

    Low: 79 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny and hot, with a high near 100. Heat index values as high as 105. South wind 3 to 8 mph.

    High: 100 °F

    Hot

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 80. South wind 3 to 5 mph.

    Low: 80 °F

    Mostly Clear

  • Friday

    Friday: Sunny and hot, with a high near 99.

    High: 99 °F

    Hot

  • Friday Night

    Friday Night: Mostly clear, with a low around 77.

    Low: 77 °F

    Mostly Clear

  • Saturday

    Saturday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny and hot, with a high near 98.

    High: 98 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

Detailed Forecast

Tonight
Clear, with a low around 77. South wind around 5 mph.
Wednesday
Sunny and hot, with a high near 98. Heat index values as high as 102. Southwest wind 5 to 8 mph.
Wednesday Night
Mostly clear, with a low around 79. South wind around 6 mph.
Thursday
Sunny and hot, with a high near 100. Heat index values as high as 105. South wind 3 to 8 mph.
Thursday Night
Mostly clear, with a low around 80. South wind 3 to 5 mph.
Friday
Sunny and hot, with a high near 99.
Friday Night
Mostly clear, with a low around 77.
Saturday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny and hot, with a high near 98.
Saturday Night
Partly cloudy, with a low around 75.
Sunday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 95.
Sunday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 72.
Labor Day
Mostly sunny, with a high near 92.
Monday Night
Partly cloudy, with a low around 70.
Tuesday
Mostly sunny, with a high near 92.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Alton IL
 38.91°N 90.16°W (Elev. 505 ft)
Last Update:
4:11 pm CDT Sep 1, 2026
Forecast Valid:
4pm CDT Sep 1, 2026-6pm CDT Sep 8, 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