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.

Mostly Cloudy

71°F

22°C

Humidity 68%
Wind Speed N 7 mph
Barometer 29.78 in (1008.3 mb)
Dewpoint 60°F (16°C)
Visibility 10.00 mi
Last update 18 Nov 1:53 pm CST
Extended Forecast for

O'Fallon IL

  • This Afternoon

    This Afternoon: A 20 percent chance of rain and thunderstorms before 4pm. Partly sunny, with a high near 70. Southwest wind 6 to 8 mph becoming north.

    High: 70 °F

    Slight Chance
    T-storms

  • Tonight

    Tonight: Mostly cloudy, with a low around 46. North wind 3 to 5 mph.

    Low: 46 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Cloudy, with a high near 58. Light and variable wind.

    High: 58 °F

    Cloudy

  • Wednesday Night

    Wednesday Night: A 20 percent chance of rain after midnight. Mostly cloudy, with a low around 48. Light southeast wind.

    Low: 48 °F

    Mostly Cloudy
    then Slight
    Chance Rain

  • Thursday

    Thursday: Rain likely and possibly a thunderstorm before noon, then rain likely between noon and 3pm, then rain likely and possibly a thunderstorm after 3pm. Cloudy, with a high near 61. South wind 5 to 8 mph. Chance of precipitation is 70%.

    High: 61 °F

    Rain Likely

  • Thursday Night

    Thursday Night: Rain likely and possibly a thunderstorm. Cloudy, with a low around 54. Chance of precipitation is 70%.

    Low: 54 °F

    Rain Likely

  • Friday

    Friday: Rain. High near 60. Chance of precipitation is 80%.

    High: 60 °F

    Rain

  • Friday Night

    Friday Night: A 50 percent chance of rain, mainly before midnight. Mostly cloudy, with a low around 43.

    Low: 43 °F

    Chance Rain
    then Slight
    Chance Rain

  • Saturday

    Saturday: Mostly sunny, with a high near 57.

    High: 57 °F

    Mostly Sunny

Detailed Forecast

This Afternoon
A 20 percent chance of rain and thunderstorms before 4pm. Partly sunny, with a high near 70. Southwest wind 6 to 8 mph becoming north.
Tonight
Mostly cloudy, with a low around 46. North wind 3 to 5 mph.
Wednesday
Cloudy, with a high near 58. Light and variable wind.
Wednesday Night
A 20 percent chance of rain after midnight. Mostly cloudy, with a low around 48. Light southeast wind.
Thursday
Rain likely and possibly a thunderstorm before noon, then rain likely between noon and 3pm, then rain likely and possibly a thunderstorm after 3pm. Cloudy, with a high near 61. South wind 5 to 8 mph. Chance of precipitation is 70%.
Thursday Night
Rain likely and possibly a thunderstorm. Cloudy, with a low around 54. Chance of precipitation is 70%.
Friday
Rain. High near 60. Chance of precipitation is 80%.
Friday Night
A 50 percent chance of rain, mainly before midnight. Mostly cloudy, with a low around 43.
Saturday
Mostly sunny, with a high near 57.
Saturday Night
Mostly clear, with a low around 39.
Sunday
Sunny, with a high near 60.
Sunday Night
Partly cloudy, with a low around 42.
Monday
A 20 percent chance of rain. Partly sunny, with a high near 61.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
O'Fallon IL
 38.59°N 89.92°W (Elev. 551 ft)
Last Update:
1:46 pm CST Nov 18, 2025
Forecast Valid:
2pm CST Nov 18, 2025-6pm CST Nov 24, 2025
 
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