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.

Mostly Cloudy

82°F

28°C

Humidity 65%
Wind Speed N 8 mph
Barometer 30.08 in (1018.2 mb)
Dewpoint 69°F (21°C)
Visibility 10.00 mi
Heat Index85°F (29°C)
Last update 7 Jul 11:53 am CDT
Extended Forecast for

Arnold MO

  • This Afternoon

    This Afternoon: A slight chance of showers, with thunderstorms also possible after 1pm. Partly sunny, with a high near 87. Northeast wind around 6 mph. Chance of precipitation is 20%.

    High: 87 °F

    Slight Chance
    T-storms

  • Tonight

    Tonight: A 20 percent chance of showers and thunderstorms before 8pm. Partly cloudy, with a low around 70. Light north wind.

    Low: 70 °F

    Slight Chance
    T-storms then
    Mostly Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 90. Calm wind.

    High: 90 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 71. Calm wind.

    Low: 71 °F

    Mostly Clear

  • Thursday

    Thursday: Mostly sunny, with a high near 95. Calm wind becoming southwest around 5 mph in the afternoon.

    High: 95 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 74. Chance of precipitation is 70%.

    Low: 74 °F

    Chance
    T-storms then
    Showers
    Likely

  • Friday

    Friday: A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 91.

    High: 91 °F

    Chance
    Showers then
    Chance
    T-storms

  • Friday Night

    Friday Night: Showers and thunderstorms likely, mainly before 1am. Mostly cloudy, with a low around 72. Chance of precipitation is 60%.

    Low: 72 °F

    T-storms
    Likely

  • Saturday

    Saturday: A 30 percent chance of showers and thunderstorms. Partly sunny, with a high near 90.

    High: 90 °F

    Chance
    T-storms

Detailed Forecast

This Afternoon
A slight chance of showers, with thunderstorms also possible after 1pm. Partly sunny, with a high near 87. Northeast wind around 6 mph. Chance of precipitation is 20%.
Tonight
A 20 percent chance of showers and thunderstorms before 8pm. Partly cloudy, with a low around 70. Light north wind.
Wednesday
Mostly sunny, with a high near 90. Calm wind.
Wednesday Night
Mostly clear, with a low around 71. Calm wind.
Thursday
Mostly sunny, with a high near 95. Calm wind becoming southwest around 5 mph in the afternoon.
Thursday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 74. Chance of precipitation is 70%.
Friday
A 50 percent chance of showers and thunderstorms. Partly sunny, with a high near 91.
Friday Night
Showers and thunderstorms likely, mainly before 1am. Mostly cloudy, with a low around 72. Chance of precipitation is 60%.
Saturday
A 30 percent chance of showers and thunderstorms. Partly sunny, with a high near 90.
Saturday Night
A 30 percent chance of showers and thunderstorms. Partly cloudy, with a low around 71.
Sunday
Mostly sunny, with a high near 91.
Sunday Night
Mostly clear, with a low around 71.
Monday
Sunny, with a high near 93.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Arnold MO
 38.42°N 90.38°W (Elev. 495 ft)
Last Update:
10:21 am CDT Jul 7, 2026
Forecast Valid:
12pm CDT Jul 7, 2026-6pm CDT Jul 13, 2026
 
Forecast Discussion
 
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Additional Resources

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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