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NWS St. Louis Announces Changes To May 16, 2025 Tornado Damage Assessment

After a year-long review of new ground survey data and aerial imagery, NWS St. Louis made several adjustments to the May 16, 2025 tornado damage assessment. Read More >

Hazardous Weather Conditions

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Fair

70°F

21°C

Humidity 82%
Wind Speed SE 5 mph
Barometer 29.87 in (1011.0 mb)
Dewpoint 64°F (18°C)
Visibility 10.00 mi
Last update 17 May 1:53 am CDT
Extended Forecast for

O'Fallon IL

  • Overnight

    Overnight: Mostly cloudy, with a low around 67. South wind around 8 mph.

    Low: 67 °F

    Mostly Cloudy

  • Sunday

    Sunday: Partly sunny, then gradually becoming sunny, with a high near 89. Breezy, with a south wind 10 to 20 mph, with gusts as high as 28 mph.

    High: 89 °F

    Mostly Sunny
    then Sunny
    and Breezy

  • Sunday Night

    Sunday Night: Increasing clouds, with a low around 72. South wind 14 to 16 mph, with gusts as high as 24 mph.

    Low: 72 °F

    Increasing
    Clouds

  • Monday

    Monday: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Partly sunny, with a high near 88. South wind 15 to 18 mph, with gusts as high as 28 mph. Chance of precipitation is 60%.

    High: 88 °F

    Showers
    Likely

  • Monday Night

    Monday Night: A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 71. South wind 14 to 17 mph, with gusts as high as 25 mph.

    Low: 71 °F

    Slight Chance
    T-storms

  • Tuesday

    Tuesday: Showers and possibly a thunderstorm. High near 87. Chance of precipitation is 100%.

    High: 87 °F

    Showers
    Likely then
    Showers

  • Tuesday Night

    Tuesday Night: Showers and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms after 1am. Low around 59. Chance of precipitation is 80%.

    Low: 59 °F

    Showers

  • Wednesday

    Wednesday: A 20 percent chance of showers before 1pm. Mostly cloudy, with a high near 71.

    High: 71 °F

    Slight Chance
    Showers

  • Wednesday Night

    Wednesday Night: A 20 percent chance of showers before 1am. Mostly cloudy, with a low around 52.

    Low: 52 °F

    Slight Chance
    Showers

Detailed Forecast

Overnight
Mostly cloudy, with a low around 67. South wind around 8 mph.
Sunday
Partly sunny, then gradually becoming sunny, with a high near 89. Breezy, with a south wind 10 to 20 mph, with gusts as high as 28 mph.
Sunday Night
Increasing clouds, with a low around 72. South wind 14 to 16 mph, with gusts as high as 24 mph.
Monday
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1pm. Partly sunny, with a high near 88. South wind 15 to 18 mph, with gusts as high as 28 mph. Chance of precipitation is 60%.
Monday Night
A 20 percent chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 71. South wind 14 to 17 mph, with gusts as high as 25 mph.
Tuesday
Showers and possibly a thunderstorm. High near 87. Chance of precipitation is 100%.
Tuesday Night
Showers and possibly a thunderstorm before 1am, then a chance of showers and thunderstorms after 1am. Low around 59. Chance of precipitation is 80%.
Wednesday
A 20 percent chance of showers before 1pm. Mostly cloudy, with a high near 71.
Wednesday Night
A 20 percent chance of showers before 1am. Mostly cloudy, with a low around 52.
Thursday
Partly sunny, with a high near 72.
Thursday Night
A 20 percent chance of showers. Mostly cloudy, with a low around 56.
Friday
A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 76.
Friday Night
A 20 percent chance of showers. Mostly cloudy, with a low around 60.
Saturday
A 20 percent chance of showers and thunderstorms. Partly sunny, with a high near 82.
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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:
1:26 am CDT May 17, 2026
Forecast Valid:
2am CDT May 17, 2026-6pm CDT May 23, 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