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.

Fog/Mist

48°F

9°C

Humidity 100%
Wind Speed Calm
Barometer 29.99 in (1015.2 mb)
Dewpoint 48°F (9°C)
Visibility 2.50 mi
Last update 11 Oct 4:53 am CDT
Extended Forecast for

Arnold MO

  • Today

    Today: Sunny, with a high near 90. Calm wind.

    High: 90 °F

    Sunny

  • Tonight

    Tonight: Increasing clouds, with a low around 66. Light and variable wind becoming south around 5 mph after midnight.

    Low: 66 °F

    Increasing
    Clouds

  • Columbus Day

    Columbus Day: Sunny, with a high near 95. Southwest wind 5 to 10 mph.

    High: 95 °F

    Sunny

  • Monday Night

    Monday Night: Clear, with a low around 70. South wind around 7 mph.

    Low: 70 °F

    Clear

  • Tuesday

    Tuesday: Sunny, with a high near 95. Southwest wind 5 to 7 mph.

    High: 95 °F

    Sunny

  • Tuesday Night

    Tuesday Night: A 50 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 70.

    Low: 70 °F

    Slight Chance
    T-storms then
    Chance
    T-storms

  • Wednesday

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

    High: 84 °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 64. Chance of precipitation is 60%.

    Low: 64 °F

    Showers
    Likely

  • Thursday

    Thursday: Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 79. Chance of precipitation is 70%.

    High: 79 °F

    Showers
    Likely

Detailed Forecast

Today
Sunny, with a high near 90. Calm wind.
Tonight
Increasing clouds, with a low around 66. Light and variable wind becoming south around 5 mph after midnight.
Columbus Day
Sunny, with a high near 95. Southwest wind 5 to 10 mph.
Monday Night
Clear, with a low around 70. South wind around 7 mph.
Tuesday
Sunny, with a high near 95. Southwest wind 5 to 7 mph.
Tuesday Night
A 50 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 70.
Wednesday
Showers and possibly a thunderstorm. High near 84. Chance of precipitation is 80%.
Wednesday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 64. Chance of precipitation is 60%.
Thursday
Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 79. Chance of precipitation is 70%.
Thursday Night
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 55.
Friday
A 20 percent chance of showers. Partly sunny, with a high near 68.
Friday Night
Partly cloudy, with a low around 43.
Saturday
Sunny, with a high near 62.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Arnold MO
 38.45°N 90.38°W (Elev. 499 ft)
Last Update:
3:16 am CDT Oct 11, 2026
Forecast Valid:
5am CDT Oct 11, 2026-6pm CDT Oct 17, 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