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

69°F

21°C

Humidity 96%
Wind Speed Calm
Barometer 29.96 in
Dewpoint 68°F (20°C)
Visibility 7.00 mi
Last update 25 Jun 4:15 am CDT
Extended Forecast for

Alton IL

Flood Watch June 25, 01:00pm until June 26, 07:00am
Click here for hazard details and duration
Flood Watch

  • Overnight

    Overnight: A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67. Calm wind.

    Low: 67 °F

    Slight Chance
    T-storms

  • Thursday

    Thursday: A 40 percent chance of showers and thunderstorms, mainly after 2pm. Mostly cloudy, with a high near 85. Light and variable wind.

    High: 85 °F

    Chance
    T-storms

  • Thursday Night

    Thursday Night: Showers and thunderstorms likely, then showers and possibly a thunderstorm after 3am. Low around 68. Light and variable wind becoming east around 6 mph after midnight. Chance of precipitation is 90%.

    Low: 68 °F

    Chance
    T-storms then
    T-storms

  • Friday

    Friday: Showers and thunderstorms before 2pm, then showers likely and possibly a thunderstorm between 2pm and 3pm, then a chance of showers and thunderstorms after 3pm. High near 81. Southeast wind 7 to 10 mph becoming southwest in the afternoon. Chance of precipitation is 90%.

    High: 81 °F

    Showers then
    Showers
    Likely

  • Friday Night

    Friday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 7pm. Mostly cloudy, with a low around 69. Southwest wind 5 to 7 mph becoming calm in the evening. Chance of precipitation is 70%.

    Low: 69 °F

    Showers
    Likely

  • Saturday

    Saturday: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 87.

    High: 87 °F

    Chance
    T-storms

  • Saturday Night

    Saturday Night: A 30 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 73.

    Low: 73 °F

    Chance
    T-storms

  • Sunday

    Sunday: Sunny, with a high near 95.

    High: 95 °F

    Sunny

  • Sunday Night

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

    Low: 76 °F

    Mostly Clear

Detailed Forecast

Overnight
A 20 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67. Calm wind.
Thursday
A 40 percent chance of showers and thunderstorms, mainly after 2pm. Mostly cloudy, with a high near 85. Light and variable wind.
Thursday Night
Showers and thunderstorms likely, then showers and possibly a thunderstorm after 3am. Low around 68. Light and variable wind becoming east around 6 mph after midnight. Chance of precipitation is 90%.
Friday
Showers and thunderstorms before 2pm, then showers likely and possibly a thunderstorm between 2pm and 3pm, then a chance of showers and thunderstorms after 3pm. High near 81. Southeast wind 7 to 10 mph becoming southwest in the afternoon. Chance of precipitation is 90%.
Friday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 7pm. Mostly cloudy, with a low around 69. Southwest wind 5 to 7 mph becoming calm in the evening. Chance of precipitation is 70%.
Saturday
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 87.
Saturday Night
A 30 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 73.
Sunday
Sunny, with a high near 95.
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
Mostly clear, with a low around 76.
Wednesday
Sunny and hot, with a high near 97.
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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:
1:51 am CDT Jun 25, 2026
Forecast Valid:
4am CDT Jun 25, 2026-6pm CDT Jul 1, 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