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

77°F

25°C

Humidity 88%
Wind Speed S 6 mph
Barometer 29.90 in (1012.0 mb)
Dewpoint 73°F (23°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 15 Jul 9:53 pm CDT
Extended Forecast for

Herculaneum MO

  • Tonight

    Tonight: Patchy fog after 4am. Otherwise, partly cloudy, with a low around 72. Light southwest wind.

    Low: 72 °F

    Partly Cloudy
    then Patchy
    Fog

  • Wednesday

    Wednesday: A slight chance of showers before noon, then a slight chance of showers and thunderstorms after 2pm. Patchy fog before 8am. Otherwise, sunny, with a high near 95. Heat index values as high as 105. Southwest wind 3 to 8 mph. Chance of precipitation is 20%.

    High: 95 °F

    Slight Chance
    T-storms and
    Patchy Fog

  • Wednesday Night

    Wednesday Night: A 20 percent chance of showers and thunderstorms before 1am. Mostly cloudy, then gradually becoming mostly clear, with a low around 75. Southwest wind 5 to 7 mph becoming calm after midnight.

    Low: 75 °F

    Slight Chance
    T-storms

  • Thursday

    Thursday: A 50 percent chance of showers and thunderstorms, mainly after 1pm. Mostly sunny, with a high near 93. Heat index values as high as 102. Calm wind becoming west around 6 mph in the morning.

    High: 93 °F

    Slight Chance
    T-storms then
    Chance
    T-storms

  • Thursday Night

    Thursday Night: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 71. Light north wind.

    Low: 71 °F

    Chance
    T-storms

  • Friday

    Friday: A 40 percent chance of showers and thunderstorms, mainly after 1pm. Mostly cloudy, with a high near 87.

    High: 87 °F

    Chance
    T-storms

  • Friday Night

    Friday Night: A 20 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 72.

    Low: 72 °F

    Slight Chance
    T-storms

  • Saturday

    Saturday: A 30 percent chance of showers and thunderstorms, mainly after 1pm. Mostly sunny, with a high near 93.

    High: 93 °F

    Chance
    T-storms

  • Saturday Night

    Saturday Night: A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74.

    Low: 74 °F

    Slight Chance
    T-storms

Detailed Forecast

Tonight
Patchy fog after 4am. Otherwise, partly cloudy, with a low around 72. Light southwest wind.
Wednesday
A slight chance of showers before noon, then a slight chance of showers and thunderstorms after 2pm. Patchy fog before 8am. Otherwise, sunny, with a high near 95. Heat index values as high as 105. Southwest wind 3 to 8 mph. Chance of precipitation is 20%.
Wednesday Night
A 20 percent chance of showers and thunderstorms before 1am. Mostly cloudy, then gradually becoming mostly clear, with a low around 75. Southwest wind 5 to 7 mph becoming calm after midnight.
Thursday
A 50 percent chance of showers and thunderstorms, mainly after 1pm. Mostly sunny, with a high near 93. Heat index values as high as 102. Calm wind becoming west around 6 mph in the morning.
Thursday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 71. Light north wind.
Friday
A 40 percent chance of showers and thunderstorms, mainly after 1pm. Mostly cloudy, with a high near 87.
Friday Night
A 20 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 72.
Saturday
A 30 percent chance of showers and thunderstorms, mainly after 1pm. Mostly sunny, with a high near 93.
Saturday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74.
Sunday
A 30 percent chance of showers and thunderstorms, mainly after 1pm. Mostly sunny, with a high near 96.
Sunday Night
A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74.
Monday
A 20 percent chance of showers and thunderstorms. Mostly sunny, with a high near 95.
Monday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 74.
Tuesday
Sunny and hot, with a high near 98.
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ABOUT THIS FORECAST

 
Point Forecast:
Herculaneum MO
 38.27°N 90.39°W (Elev. 456 ft)
Last Update:
7:37 pm CDT Jul 15, 2025
Forecast Valid:
9pm CDT Jul 15, 2025-6pm CDT Jul 22, 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