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.

Partly Cloudy

66°F

19°C

Humidity 84%
Wind Speed S 12 G 28 mph
Barometer 29.54 in (1000.1 mb)
Dewpoint 61°F (16°C)
Visibility 10.00 mi
Last update 8 Jan 7:53 pm CST
Extended Forecast for

O'Fallon IL

  • Tonight

    Tonight: Rain and thunderstorms likely, mainly before 11pm. Mostly cloudy, then gradually becoming mostly clear, with a low around 48. Breezy, with a south wind 15 to 22 mph becoming west after midnight. Winds could gust as high as 37 mph. Chance of precipitation is 70%.

    Low: 48 °F

    Rain Likely
    and Breezy
    then Partly
    Cloudy

  • Friday

    Friday: Mostly cloudy, with a high near 54. West wind 11 to 16 mph becoming north 5 to 10 mph in the afternoon. Winds could gust as high as 25 mph.

    High: 54 °F

    Mostly Cloudy

  • Friday Night

    Friday Night: A 20 percent chance of rain after midnight. Mostly cloudy, with a low around 39. North wind around 5 mph becoming calm.

    Low: 39 °F

    Mostly Cloudy
    then Slight
    Chance Rain

  • Saturday

    Saturday: A 20 percent chance of rain before noon. Cloudy through mid morning, then gradual clearing, with a high near 45. Northwest wind 6 to 14 mph, with gusts as high as 23 mph.

    High: 45 °F

    Slight Chance
    Rain then
    Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 25. West wind 10 to 15 mph, with gusts as high as 23 mph.

    Low: 25 °F

    Partly Cloudy

  • Sunday

    Sunday: Sunny, with a high near 35.

    High: 35 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 24.

    Low: 24 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 51.

    High: 51 °F

    Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 35.

    Low: 35 °F

    Partly Cloudy

Detailed Forecast

Tonight
Rain and thunderstorms likely, mainly before 11pm. Mostly cloudy, then gradually becoming mostly clear, with a low around 48. Breezy, with a south wind 15 to 22 mph becoming west after midnight. Winds could gust as high as 37 mph. Chance of precipitation is 70%.
Friday
Mostly cloudy, with a high near 54. West wind 11 to 16 mph becoming north 5 to 10 mph in the afternoon. Winds could gust as high as 25 mph.
Friday Night
A 20 percent chance of rain after midnight. Mostly cloudy, with a low around 39. North wind around 5 mph becoming calm.
Saturday
A 20 percent chance of rain before noon. Cloudy through mid morning, then gradual clearing, with a high near 45. Northwest wind 6 to 14 mph, with gusts as high as 23 mph.
Saturday Night
Partly cloudy, with a low around 25. West wind 10 to 15 mph, with gusts as high as 23 mph.
Sunday
Sunny, with a high near 35.
Sunday Night
Mostly clear, with a low around 24.
Monday
Sunny, with a high near 51.
Monday Night
Partly cloudy, with a low around 35.
Tuesday
Partly sunny, with a high near 55.
Tuesday Night
A 20 percent chance of rain. Mostly cloudy, with a low around 36.
Wednesday
Mostly cloudy, with a high near 42.
Wednesday Night
Mostly cloudy, with a low around 25.
Thursday
Mostly sunny, with a high near 38.
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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:
3:57 pm CST Jan 8, 2026
Forecast Valid:
8pm CST Jan 8, 2026-6pm CST Jan 15, 2026
 
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Additional Resources

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Hourly Weather Forecast

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation