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.

Fog/Mist

49°F

9°C

Humidity 97%
Wind Speed N 6 mph
Barometer 30.01 in (1016.2 mb)
Dewpoint 48°F (9°C)
Visibility 3.00 mi
Wind Chill46°F (8°C)
Last update 22 Nov 2:53 am CST
Extended Forecast for

O'Fallon IL

  • Overnight

    Overnight: Patchy drizzle and fog. Cloudy, with a low around 46. North wind around 7 mph.

    Low: 46 °F

    Patchy
    Drizzle and
    Patchy Fog

  • Saturday

    Saturday: Patchy drizzle before 7am. Cloudy through mid morning, then gradual clearing, with a high near 56. North wind 5 to 8 mph becoming west in the afternoon.

    High: 56 °F

    Patchy
    Drizzle then
    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 42. West wind 5 to 7 mph.

    Low: 42 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 59. Northwest wind around 6 mph becoming calm in the afternoon.

    High: 59 °F

    Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 42. Calm wind becoming southeast around 5 mph after midnight.

    Low: 42 °F

    Partly Cloudy

  • Monday

    Monday: Showers likely after noon. Cloudy, with a high near 57. Chance of precipitation is 60%.

    High: 57 °F

    Mostly Cloudy
    then Showers
    Likely

  • Monday Night

    Monday Night: Showers, mainly before midnight. Low around 50. Chance of precipitation is 90%.

    Low: 50 °F

    Showers then
    Chance
    Showers

  • Tuesday

    Tuesday: Partly sunny, with a high near 64.

    High: 64 °F

    Partly Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 36.

    Low: 36 °F

    Partly Cloudy

Detailed Forecast

Overnight
Patchy drizzle and fog. Cloudy, with a low around 46. North wind around 7 mph.
Saturday
Patchy drizzle before 7am. Cloudy through mid morning, then gradual clearing, with a high near 56. North wind 5 to 8 mph becoming west in the afternoon.
Saturday Night
Mostly clear, with a low around 42. West wind 5 to 7 mph.
Sunday
Sunny, with a high near 59. Northwest wind around 6 mph becoming calm in the afternoon.
Sunday Night
Partly cloudy, with a low around 42. Calm wind becoming southeast around 5 mph after midnight.
Monday
Showers likely after noon. Cloudy, with a high near 57. Chance of precipitation is 60%.
Monday Night
Showers, mainly before midnight. Low around 50. Chance of precipitation is 90%.
Tuesday
Partly sunny, with a high near 64.
Tuesday Night
Partly cloudy, with a low around 36.
Wednesday
Mostly sunny, with a high near 49.
Wednesday Night
Partly cloudy, with a low around 30.
Thanksgiving Day
Mostly sunny, with a high near 46.
Thursday Night
Partly cloudy, with a low around 28.
Friday
Mostly sunny, with a high near 45.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
O'Fallon IL
 38.59°N 89.92°W (Elev. 551 ft)
Last Update:
3:16 am CST Nov 22, 2025
Forecast Valid:
3am CST Nov 22, 2025-6pm CST Nov 28, 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