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

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Fair

90°F

32°C

Humidity 38%
Wind Speed SW 8 mph
Barometer 29.93 in (1012.9 mb)
Dewpoint 61°F (16°C)
Visibility 10.00 mi
Heat Index90°F (32°C)
Last update 12 Oct 12:53 pm CDT
Extended Forecast for

Herculaneum MO

  • Columbus Day

    Columbus Day: Sunny, with a high near 94. Southwest wind around 10 mph, with gusts as high as 20 mph.

    High: 94 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 67. South wind 3 to 8 mph.

    Low: 67 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 96. Heat index values as high as 102. Southwest wind 3 to 8 mph.

    High: 96 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 40 percent chance of showers and thunderstorms, mainly after 3am. Increasing clouds, with a low around 71. South wind 3 to 6 mph.

    Low: 71 °F

    Mostly Clear
    then Chance
    Showers

  • Wednesday

    Wednesday: Showers and possibly a thunderstorm. High near 81. Light southwest wind. Chance of precipitation is 100%.

    High: 81 °F

    Showers

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 65. Chance of precipitation is 70%.

    Low: 65 °F

    Chance
    T-storms then
    Showers
    Likely

  • Thursday

    Thursday: Showers and possibly a thunderstorm. High near 84. Chance of precipitation is 80%.

    High: 84 °F

    Showers

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 1am, then a slight chance of showers. Mostly cloudy, with a low around 52. Chance of precipitation is 30%.

    Low: 52 °F

    Chance
    Showers

  • Friday

    Friday: Partly sunny, with a high near 65.

    High: 65 °F

    Partly Sunny

Detailed Forecast

Columbus Day
Sunny, with a high near 94. Southwest wind around 10 mph, with gusts as high as 20 mph.
Tonight
Mostly clear, with a low around 67. South wind 3 to 8 mph.
Tuesday
Sunny, with a high near 96. Heat index values as high as 102. Southwest wind 3 to 8 mph.
Tuesday Night
A 40 percent chance of showers and thunderstorms, mainly after 3am. Increasing clouds, with a low around 71. South wind 3 to 6 mph.
Wednesday
Showers and possibly a thunderstorm. High near 81. Light southwest wind. Chance of precipitation is 100%.
Wednesday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 65. Chance of precipitation is 70%.
Thursday
Showers and possibly a thunderstorm. High near 84. Chance of precipitation is 80%.
Thursday Night
A chance of showers and thunderstorms before 1am, then a slight chance of showers. Mostly cloudy, with a low around 52. Chance of precipitation is 30%.
Friday
Partly sunny, with a high near 65.
Friday Night
Mostly clear, with a low around 38.
Saturday
Sunny, with a high near 64.
Saturday Night
Mostly clear, with a low around 37.
Sunday
Sunny, with a high near 72.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Herculaneum MO
 38.27°N 90.39°W (Elev. 456 ft)
Last Update:
1:25 pm CDT Oct 12, 2026
Forecast Valid:
1pm CDT Oct 12, 2026-6pm CDT Oct 18, 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