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.

Fog/Mist

76°F

24°C

Humidity 95%
Wind Speed Calm
Barometer 30.02 in
Dewpoint 74°F (23°C)
Visibility 5.00 mi
Heat Index75°F (24°C)
Last update 18 Aug 1:55 am CDT
Extended Forecast for

3 Miles SSW Piasa IL

Heat Advisory August 18, 02:15am until August 18, 08:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory August 18, 02:15am until August 18, 08:00pm

    NOW until 8:00pm Mon

    Heat Advisory

  • Overnight

    Low: 76 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 93. Heat index values as high as 102. South wind 5 to 7 mph.

    High: 93 °F

    Sunny

  • Monday Night

    Monday Night: A 20 percent chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 72. South wind 3 to 5 mph.

    Low: 72 °F

    Partly Cloudy
    then Slight
    Chance
    T-storms

  • Tuesday

    Tuesday: A 40 percent chance of showers and thunderstorms. Mostly sunny, with a high near 91. Light and variable wind becoming west around 6 mph in the morning.

    High: 91 °F

    Chance
    Showers then
    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: A chance of showers and thunderstorms before 4am, then a slight chance of showers. Partly cloudy, with a low around 72. North wind 3 to 5 mph. Chance of precipitation is 30%.

    Low: 72 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: A slight chance of showers, with thunderstorms also possible after 10am. Mostly sunny, with a high near 85. Chance of precipitation is 20%.

    High: 85 °F

    Slight Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 64.

    Low: 64 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 83.

    High: 83 °F

    Sunny

Detailed Forecast

Overnight
Mostly clear, with a low around 76. Light southeast wind.
Monday
Sunny, with a high near 93. Heat index values as high as 102. South wind 5 to 7 mph.
Monday Night
A 20 percent chance of showers and thunderstorms after 1am. Partly cloudy, with a low around 72. South wind 3 to 5 mph.
Tuesday
A 40 percent chance of showers and thunderstorms. Mostly sunny, with a high near 91. Light and variable wind becoming west around 6 mph in the morning.
Tuesday Night
A chance of showers and thunderstorms before 4am, then a slight chance of showers. Partly cloudy, with a low around 72. North wind 3 to 5 mph. Chance of precipitation is 30%.
Wednesday
A slight chance of showers, with thunderstorms also possible after 10am. Mostly sunny, with a high near 85. Chance of precipitation is 20%.
Wednesday Night
Mostly clear, with a low around 64.
Thursday
Sunny, with a high near 83.
Thursday Night
Clear, with a low around 63.
Friday
Sunny, with a high near 85.
Friday Night
Mostly clear, with a low around 65.
Saturday
Sunny, with a high near 84.
Saturday Night
Mostly clear, with a low around 60.
Sunday
Sunny, with a high near 79.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
3 Miles SSW Piasa IL
 39.08°N 90.15°W (Elev. 610 ft)
Last Update:
2:06 am CDT Aug 18, 2025
Forecast Valid:
2am CDT Aug 18, 2025-6pm CDT Aug 24, 2025
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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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