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.

Partly Cloudy

77°F

25°C

Humidity 83%
Wind Speed Calm
Barometer 29.96 in
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 25 Jun 7:45 pm CDT
Extended Forecast for

Alton IL

Flood Watch June 25, 07:55pm until June 26, 07:00pm
Click here for hazard details and duration
Flood Watch
  •  
    Flood Watch June 25, 07:55pm until June 26, 07:00pm

    NOW until 7:00pm Fri

    Flood Watch

  • Tonight

    Low: 68 °F

    Showers

  • Friday

    Friday: Showers and thunderstorms, mainly before 4pm. High near 80. Southeast wind 7 to 10 mph becoming southwest in the afternoon. Chance of precipitation is 90%.

    High: 80 °F

    Showers then
    T-storms

  • Friday Night

    Friday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 67. Southwest wind 5 to 8 mph becoming light and variable in the evening. Chance of precipitation is 50%.

    Low: 67 °F

    Chance
    T-storms then
    Chance
    Showers

  • Saturday

    Saturday: A slight chance of showers before 7am, then a chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 84. Light and variable wind. Chance of precipitation is 30%.

    High: 84 °F

    Mostly Cloudy
    then Chance
    T-storms

  • Saturday Night

    Saturday Night: A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 72. Southeast wind around 6 mph.

    Low: 72 °F

    Chance
    T-storms

  • Sunday

    Sunday: Sunny, with a high near 94.

    High: 94 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 76.

    Low: 76 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 96.

    High: 96 °F

    Sunny

Detailed Forecast

Tonight
Showers and possibly a thunderstorm. Low around 68. Light and variable wind becoming southeast around 6 mph after midnight. Chance of precipitation is 90%.
Friday
Showers and thunderstorms, mainly before 4pm. High near 80. Southeast wind 7 to 10 mph becoming southwest in the afternoon. Chance of precipitation is 90%.
Friday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 67. Southwest wind 5 to 8 mph becoming light and variable in the evening. Chance of precipitation is 50%.
Saturday
A slight chance of showers before 7am, then a chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 84. Light and variable wind. Chance of precipitation is 30%.
Saturday Night
A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 72. Southeast wind around 6 mph.
Sunday
Sunny, with a high near 94.
Sunday Night
Mostly clear, with a low around 76.
Monday
Sunny, with a high near 96.
Monday Night
Mostly clear, with a low around 77.
Tuesday
Sunny and hot, with a high near 97.
Tuesday Night
Clear, with a low around 77.
Wednesday
Sunny and hot, with a high near 97.
Wednesday Night
Mostly clear, with a low around 77.
Thursday
Sunny, with a high near 96.
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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:
5:26 pm CDT Jun 25, 2026
Forecast Valid:
7pm CDT Jun 25, 2026-6pm CDT Jul 2, 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