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.

N/A

Humidity NA
Wind Speed NA
Barometer NA
Dewpoint N/A
Visibility NA
Last update *** Not a current observation ***
Extended Forecast for

Arnold MO

  • Tonight

    Tonight: Patchy fog after 4am. Otherwise, mostly cloudy, then gradually becoming clear, with a low around 36. Northwest wind 5 to 7 mph becoming calm in the evening.

    Low: 36 °F

    Mostly Cloudy
    then Patchy
    Fog

  • Sunday

    Sunday: Patchy fog before 7am. Otherwise, sunny, with a high near 68. Calm wind becoming southwest around 6 mph in the morning.

    High: 68 °F

    Patchy Fog
    then Sunny

  • Sunday Night

    Sunday Night: Clear, with a low around 48. South wind 3 to 6 mph.

    Low: 48 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 79. South wind 5 to 10 mph, with gusts as high as 20 mph.

    High: 79 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 61. South wind around 7 mph.

    Low: 61 °F

    Mostly Clear

  • Tuesday

    Tuesday: A slight chance of showers and thunderstorms before 9am, then a slight chance of showers between 9am and noon, then a chance of showers and thunderstorms after noon. Mostly sunny, with a high near 82. Chance of precipitation is 50%.

    High: 82 °F

    Slight Chance
    T-storms then
    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Showers and possibly a thunderstorm. Low around 53. Chance of precipitation is 90%.

    Low: 53 °F

    Showers

  • Wednesday

    Wednesday: Showers and possibly a thunderstorm before noon, then showers likely. High near 66. Chance of precipitation is 100%.

    High: 66 °F

    Showers then
    Showers
    Likely

  • Wednesday Night

    Wednesday Night: A 20 percent chance of showers before midnight. Mostly clear, with a low around 32.

    Low: 32 °F

    Slight Chance
    Showers then
    Mostly Clear

Detailed Forecast

Tonight
Patchy fog after 4am. Otherwise, mostly cloudy, then gradually becoming clear, with a low around 36. Northwest wind 5 to 7 mph becoming calm in the evening.
Sunday
Patchy fog before 7am. Otherwise, sunny, with a high near 68. Calm wind becoming southwest around 6 mph in the morning.
Sunday Night
Clear, with a low around 48. South wind 3 to 6 mph.
Monday
Sunny, with a high near 79. South wind 5 to 10 mph, with gusts as high as 20 mph.
Monday Night
Mostly clear, with a low around 61. South wind around 7 mph.
Tuesday
A slight chance of showers and thunderstorms before 9am, then a slight chance of showers between 9am and noon, then a chance of showers and thunderstorms after noon. Mostly sunny, with a high near 82. Chance of precipitation is 50%.
Tuesday Night
Showers and possibly a thunderstorm. Low around 53. Chance of precipitation is 90%.
Wednesday
Showers and possibly a thunderstorm before noon, then showers likely. High near 66. Chance of precipitation is 100%.
Wednesday Night
A 20 percent chance of showers before midnight. Mostly clear, with a low around 32.
Thursday
Sunny, with a high near 54.
Thursday Night
Mostly cloudy, with a low around 41.
Friday
Partly sunny, with a high near 68.
Friday Night
Mostly cloudy, with a low around 39.
Saturday
Mostly cloudy, with a high near 58.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Arnold MO
 38.45°N 90.38°W (Elev. 499 ft)
Last Update:
2:11 pm CST Mar 7, 2026
Forecast Valid:
4pm CST Mar 7, 2026-6pm CDT Mar 14, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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