National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Fog/Mist

67°F

19°C

Humidity 97%
Wind Speed NE 6 mph
Barometer 30.01 in (1015.8 mb)
Dewpoint 66°F (19°C)
Visibility 5.00 mi
Last update 15 Jun 4:53 am CDT
Extended Forecast for

O'Fallon IL

  • Today

    Today: Patchy fog before 7am. Otherwise, partly sunny, with a high near 84. Northeast wind 3 to 6 mph.

    High: 84 °F

    Patchy Fog
    then Mostly
    Cloudy

  • Tonight

    Tonight: Mostly cloudy, with a low around 69. Northeast wind around 6 mph becoming calm in the evening.

    Low: 69 °F

    Mostly Cloudy

  • Monday

    Monday: A 40 percent chance of showers and thunderstorms, mainly between 1pm and 4pm. Mostly cloudy, with a high near 84. East wind 3 to 6 mph.

    High: 84 °F

    Chance
    T-storms

  • Monday Night

    Monday Night: Partly cloudy, with a low around 69. Light south wind.

    Low: 69 °F

    Partly Cloudy

  • Tuesday

    Tuesday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 90. South wind 3 to 8 mph.

    High: 90 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: A 40 percent chance of showers and thunderstorms, mainly after 1am. Mostly cloudy, with a low around 74.

    Low: 74 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: Showers and thunderstorms likely, mainly after 1pm. Partly sunny, with a high near 87. Chance of precipitation is 60%.

    High: 87 °F

    T-storms
    Likely

  • Wednesday Night

    Wednesday Night: A 40 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 69.

    Low: 69 °F

    Chance
    T-storms

  • Juneteenth

    Juneteenth: Mostly sunny, with a high near 86.

    High: 86 °F

    Mostly Sunny

Detailed Forecast

Today
Patchy fog before 7am. Otherwise, partly sunny, with a high near 84. Northeast wind 3 to 6 mph.
Tonight
Mostly cloudy, with a low around 69. Northeast wind around 6 mph becoming calm in the evening.
Monday
A 40 percent chance of showers and thunderstorms, mainly between 1pm and 4pm. Mostly cloudy, with a high near 84. East wind 3 to 6 mph.
Monday Night
Partly cloudy, with a low around 69. Light south wind.
Tuesday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 90. South wind 3 to 8 mph.
Tuesday Night
A 40 percent chance of showers and thunderstorms, mainly after 1am. Mostly cloudy, with a low around 74.
Wednesday
Showers and thunderstorms likely, mainly after 1pm. Partly sunny, with a high near 87. Chance of precipitation is 60%.
Wednesday Night
A 40 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 69.
Juneteenth
Mostly sunny, with a high near 86.
Thursday Night
Mostly clear, with a low around 69.
Friday
Sunny, with a high near 90.
Friday Night
Mostly clear, with a low around 74.
Saturday
Sunny, with a high near 94.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
O'Fallon IL
 38.59°N 89.95°W (Elev. 545 ft)
Last Update:
5:22 am CDT Jun 15, 2025
Forecast Valid:
5am CDT Jun 15, 2025-6pm CDT Jun 21, 2025
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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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