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

Hazardous Weather Conditions

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Fair

82°F

28°C

Humidity 100%
Wind Speed Calm
Barometer 30.05 in
Dewpoint 82°F (28°C)
Visibility 10.00 mi
Heat Index95°F (35°C)
Last update 30 Jul 7:53 am CDT
Extended Forecast for

Herculaneum MO

Extreme Heat Warning July 30, 08:46am until July 30, 07:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning July 30, 08:46am until July 30, 07:00pm

    NOW until 7:00pm Wed

    Extreme Heat Warning

  • Today

    High: 98 °F

    Sunny then
    Scattered
    T-storms

  • Tonight

    Tonight: Scattered showers and thunderstorms. Mostly cloudy, with a low around 72. Calm wind. Chance of precipitation is 50%.

    Low: 72 °F

    Scattered
    T-storms

  • Thursday

    Thursday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Mostly cloudy, with a high near 84. Calm wind becoming north 5 to 7 mph in the afternoon. Chance of precipitation is 60%.

    High: 84 °F

    Chance
    T-storms then
    Showers
    Likely

  • Thursday Night

    Thursday Night: A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Mostly cloudy, with a low around 65. North wind 5 to 7 mph. Chance of precipitation is 20%.

    Low: 65 °F

    Slight Chance
    T-storms then
    Slight Chance
    Showers

  • Friday

    Friday: Mostly sunny, with a high near 80. North wind 6 to 8 mph.

    High: 80 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 59.

    Low: 59 °F

    Partly Cloudy

  • Saturday

    Saturday: Sunny, with a high near 81.

    High: 81 °F

    Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 58.

    Low: 58 °F

    Mostly Clear

Detailed Forecast

Today
Scattered showers and thunderstorms, mainly after 5pm. Sunny and hot, with a high near 98. Heat index values as high as 107. Calm wind. Chance of precipitation is 30%.
Tonight
Scattered showers and thunderstorms. Mostly cloudy, with a low around 72. Calm wind. Chance of precipitation is 50%.
Thursday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Mostly cloudy, with a high near 84. Calm wind becoming north 5 to 7 mph in the afternoon. Chance of precipitation is 60%.
Thursday Night
A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers between 10pm and 1am. Mostly cloudy, with a low around 65. North wind 5 to 7 mph. Chance of precipitation is 20%.
Friday
Mostly sunny, with a high near 80. North wind 6 to 8 mph.
Friday Night
Partly cloudy, with a low around 59.
Saturday
Sunny, with a high near 81.
Saturday Night
Mostly clear, with a low around 58.
Sunday
Sunny, with a high near 84.
Sunday Night
Partly cloudy, with a low around 64.
Monday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 85.
Monday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 66.
Tuesday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 89.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Herculaneum MO
 38.27°N 90.39°W (Elev. 456 ft)
Last Update:
8:31 am CDT Jul 30, 2025
Forecast Valid:
8am CDT Jul 30, 2025-6pm CDT Aug 5, 2025
 
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