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: Partly cloudy, with a low around 31. North wind 6 to 10 mph.

    Low: 31 °F

    Partly Cloudy

  • Sunday

    Sunday: Partly sunny, with a high near 48. Northeast wind 8 to 10 mph.

    High: 48 °F

    Partly Sunny

  • Sunday Night

    Sunday Night: Rain and snow likely before midnight, then rain and snow, possibly mixed with sleet between midnight and 3am, then rain, possibly mixed with snow after 3am. Low around 33. Northeast wind around 6 mph. Chance of precipitation is 80%. Little or no snow and sleet accumulation expected.

    Low: 33 °F

    Wintry Mix

  • Monday

    Monday: Rain likely, mainly before noon. Cloudy, with a high near 46. East wind around 7 mph. Chance of precipitation is 60%.

    High: 46 °F

    Rain Likely
    then Slight
    Chance Rain

  • Monday Night

    Monday Night: Rain. Low around 40. Southeast wind around 6 mph. Chance of precipitation is 80%.

    Low: 40 °F

    Rain

  • Tuesday

    Tuesday: Rain and possibly a thunderstorm before noon, then a chance of rain and thunderstorms between noon and 3pm, then a chance of rain after 3pm. High near 67. Chance of precipitation is 80%.

    High: 67 °F

    Rain then
    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Rain and possibly a thunderstorm. Low around 54. Chance of precipitation is 80%.

    Low: 54 °F

    Rain

  • Wednesday

    Wednesday: Rain and possibly a thunderstorm. High near 70. Chance of precipitation is 80%.

    High: 70 °F

    Rain

  • Wednesday Night

    Wednesday Night: Rain likely and possibly a thunderstorm. Mostly cloudy, with a low around 53. Chance of precipitation is 70%.

    Low: 53 °F

    Rain Likely

Detailed Forecast

Tonight
Partly cloudy, with a low around 31. North wind 6 to 10 mph.
Sunday
Partly sunny, with a high near 48. Northeast wind 8 to 10 mph.
Sunday Night
Rain and snow likely before midnight, then rain and snow, possibly mixed with sleet between midnight and 3am, then rain, possibly mixed with snow after 3am. Low around 33. Northeast wind around 6 mph. Chance of precipitation is 80%. Little or no snow and sleet accumulation expected.
Monday
Rain likely, mainly before noon. Cloudy, with a high near 46. East wind around 7 mph. Chance of precipitation is 60%.
Monday Night
Rain. Low around 40. Southeast wind around 6 mph. Chance of precipitation is 80%.
Tuesday
Rain and possibly a thunderstorm before noon, then a chance of rain and thunderstorms between noon and 3pm, then a chance of rain after 3pm. High near 67. Chance of precipitation is 80%.
Tuesday Night
Rain and possibly a thunderstorm. Low around 54. Chance of precipitation is 80%.
Wednesday
Rain and possibly a thunderstorm. High near 70. Chance of precipitation is 80%.
Wednesday Night
Rain likely and possibly a thunderstorm. Mostly cloudy, with a low around 53. Chance of precipitation is 70%.
Thursday
Rain likely. Partly sunny, with a high near 73. Chance of precipitation is 60%.
Thursday Night
A 50 percent chance of rain and thunderstorms. Mostly cloudy, with a low around 57.
Friday
Rain likely and possibly a thunderstorm. Mostly cloudy, with a high near 75. Chance of precipitation is 60%.
Friday Night
Rain likely and possibly a thunderstorm. Mostly cloudy, with a low around 54. Chance of precipitation is 70%.
Saturday
Rain likely. Mostly cloudy, with a high near 68. Chance of precipitation is 70%.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Arnold MO
 38.42°N 90.35°W (Elev. 400 ft)
Last Update:
8:21 pm CST Feb 28, 2026
Forecast Valid:
9pm CST Feb 28, 2026-6pm CST Mar 7, 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