Threats of Heavy Rainfall, Severe Thunderstorms and Dangerous Heat

Several complexes of thunderstorms, some severe with heavy rainfall, will impact areas from the northern Plains, Great Lakes, Ohio Valley to the mid-Atlantic. This threat will shift toward the Carolinas on Friday. Heavy rainfall, remnants of Edouard, continues for portions of eastern Texas through today. In-between these systems, a dome of high pressure and heat for central and eastern states. Read More >

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

A Few Clouds

97°F

36°C

Humidity 42%
Wind Speed Vrbl 7 mph
Barometer 29.97 in (1014.4 mb)
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Heat Index104°F (40°C)
Last update 3 Sep 12:53 pm CDT
Extended Forecast for

Herculaneum MO

Extreme Heat Warning until September 5, 08:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning until September 5, 08:00pm

    NOW until 8:00pm Sat

    Extreme Heat Warning

  • This Afternoon

    High: 99 °F

    Hot

  • Tonight

    Tonight: Mostly clear, with a low around 74. Light south wind.

    Low: 74 °F

    Mostly Clear

  • Friday

    Friday: Sunny and hot, with a high near 100. Heat index values as high as 109. Light and variable wind.

    High: 100 °F

    Hot

  • Friday Night

    Friday Night: Mostly clear, with a low around 75. Calm wind.

    Low: 75 °F

    Mostly Clear

  • Saturday

    Saturday: Sunny and hot, with a high near 100. Light west wind.

    High: 100 °F

    Hot

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 72.

    Low: 72 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 96.

    High: 96 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 65.

    Low: 65 °F

    Mostly Clear

Detailed Forecast

This Afternoon
Mostly sunny and hot, with a high near 99. Heat index values as high as 107. Calm wind becoming south around 5 mph.
Tonight
Mostly clear, with a low around 74. Light south wind.
Friday
Sunny and hot, with a high near 100. Heat index values as high as 109. Light and variable wind.
Friday Night
Mostly clear, with a low around 75. Calm wind.
Saturday
Sunny and hot, with a high near 100. Light west wind.
Saturday Night
Mostly clear, with a low around 72.
Sunday
Sunny, with a high near 96.
Sunday Night
Mostly clear, with a low around 65.
Labor Day
Sunny, with a high near 93.
Monday Night
Mostly clear, with a low around 66.
Tuesday
Sunny and hot, with a high near 97.
Tuesday Night
Mostly clear, with a low around 74.
Wednesday
Sunny and hot, with a high near 99.
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ABOUT THIS FORECAST

 
Point Forecast:
Herculaneum MO
 38.27°N 90.39°W (Elev. 456 ft)
1:25 pm CDT Sep 3, 2026
1pm CDT Sep 3, 2026-6pm CDT Sep 9, 2026
 
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Additional Resources

Radar & Satellite Image

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Hourly Weather Forecast

National Digital Forecast Database