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

85°F

29°C

Humidity 59%
Wind Speed NE 7 mph
Barometer 30.02 in (1016.2 mb)
Dewpoint 69°F (21°C)
Visibility 10.00 mi
Heat Index89°F (32°C)
Last update 7 Jul 6:53 pm CDT
Extended Forecast for

Arnold MO

  • 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. Heat index values as high as 103. 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. South wind 3 to 5 mph. 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 possibly a thunderstorm. Low around 72. Chance of precipitation is 80%.

    Low: 72 °F

    T-storms

  • Saturday

    Saturday: A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 88.

    High: 88 °F

    Chance
    Showers then
    Chance
    T-storms

  • Saturday Night

    Saturday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 70. Chance of precipitation is 40%.

    Low: 70 °F

    Chance
    T-storms

Detailed Forecast

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. Heat index values as high as 103. 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. South wind 3 to 5 mph. 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 possibly a thunderstorm. Low around 72. Chance of precipitation is 80%.
Saturday
A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 88.
Saturday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 70. Chance of precipitation is 40%.
Sunday
A slight chance of showers, with thunderstorms also possible after 1pm. Mostly sunny, with a high near 89. Chance of precipitation is 20%.
Sunday Night
Mostly clear, with a low around 70.
Monday
Sunny, with a high near 91.
Monday Night
Mostly clear, with a low around 71.
Tuesday
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:
5:11 pm CDT Jul 7, 2026
Forecast Valid:
7pm CDT Jul 7, 2026-6pm CDT Jul 14, 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