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

Hazardous Weather Conditions

Current conditions at

St. Louis Lambert International Airport (KSTL)

Lat: 38.75°NLon: 90.37°WElev: 604ft.

Mostly Cloudy

87°F

31°C

Humidity 59%
Wind Speed E 3 mph
Barometer 30.02 in (1015.0 mb)
Dewpoint 71°F (22°C)
Visibility 10.00 mi
Heat Index93°F (34°C)
Last update 16 Aug 6:51 pm CDT
Extended Forecast for

Clayton MO

Heat Advisory August 16, 06:57pm until August 18, 08:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory August 16, 06:57pm until August 18, 08:00pm

    NOW until 8:00pm Mon

    Heat Advisory

  • Tonight

    Low: 79 °F

    Slight Chance
    T-storms then
    Mostly Clear

  • Sunday

    Sunday: A 30 percent chance of showers and thunderstorms, mainly after 5pm. Mostly sunny and hot, with a high near 99. Heat index values as high as 106. Calm wind becoming southeast around 5 mph in the afternoon.

    High: 99 °F

    Sunny then
    Chance
    T-storms

  • Sunday Night

    Sunday Night: A 30 percent chance of showers and thunderstorms, mainly before 8pm. Partly cloudy, with a low around 78. Light and variable wind.

    Low: 78 °F

    Chance
    T-storms then
    Mostly Clear

  • Monday

    Monday: Sunny and hot, with a high near 97. Heat index values as high as 105. Calm wind becoming south around 5 mph in the afternoon.

    High: 97 °F

    Hot

  • Monday Night

    Monday Night: Mostly clear, with a low around 79. Southeast wind around 5 mph becoming calm in the evening.

    Low: 79 °F

    Mostly Clear

  • Tuesday

    Tuesday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 95.

    High: 95 °F

    Sunny then
    Slight Chance
    T-storms

  • Tuesday Night

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

    Low: 73 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: A slight chance of showers, with thunderstorms also possible after 1pm. Partly sunny, with a high near 84. Chance of precipitation is 20%.

    High: 84 °F

    Slight Chance
    Showers then
    Slight Chance
    T-storms

Detailed Forecast

Tonight
A 20 percent chance of showers and thunderstorms before 8pm. Cloudy during the early evening, then gradual clearing, with a low around 79. Light and variable wind.
Sunday
A 30 percent chance of showers and thunderstorms, mainly after 5pm. Mostly sunny and hot, with a high near 99. Heat index values as high as 106. Calm wind becoming southeast around 5 mph in the afternoon.
Sunday Night
A 30 percent chance of showers and thunderstorms, mainly before 8pm. Partly cloudy, with a low around 78. Light and variable wind.
Monday
Sunny and hot, with a high near 97. Heat index values as high as 105. Calm wind becoming south around 5 mph in the afternoon.
Monday Night
Mostly clear, with a low around 79. Southeast wind around 5 mph becoming calm in the evening.
Tuesday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 95.
Tuesday Night
A 30 percent chance of showers and thunderstorms, mainly before 1am. Partly cloudy, with a low around 73.
Wednesday
A slight chance of showers, with thunderstorms also possible after 1pm. Partly sunny, with a high near 84. Chance of precipitation is 20%.
Wednesday Night
Partly cloudy, with a low around 68.
Thursday
Mostly sunny, with a high near 84.
Thursday Night
Mostly clear, with a low around 67.
Friday
Sunny, with a high near 87.
Friday Night
Mostly clear, with a low around 68.
Saturday
Sunny, with a high near 90.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Clayton MO
 38.64°N 90.32°W (Elev. 558 ft)
Last Update:
5:56 pm CDT Aug 16, 2025
Forecast Valid:
6pm CDT Aug 16, 2025-6pm CDT Aug 23, 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