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

Hazardous Weather Conditions

Current conditions at

St. Louis, Spirit Of St. Louis Airport (KSUS)

Lat: 38.66°NLon: 90.66°WElev: 463ft.

Fair

71°F

22°C

Humidity 73%
Wind Speed E 5 mph
Barometer 29.90 in (1011.8 mb)
Dewpoint 62°F (17°C)
Visibility 10.00 mi
Last update 21 Jun 12:54 am CDT
Extended Forecast for

O'Fallon MO

Flood Watch June 21, 07:00am until June 22, 01:00am
Click here for hazard details and duration
Flood Watch

  • Overnight

    Overnight: Mostly cloudy, with a low around 68. East wind 3 to 6 mph.

    Low: 68 °F

    Mostly Cloudy

  • Sunday

    Sunday: Showers and thunderstorms. High near 84. Southeast wind 8 to 13 mph becoming southwest in the afternoon. Winds could gust as high as 26 mph. Chance of precipitation is 80%.

    High: 84 °F

    T-storms

  • Sunday Night

    Sunday Night: Showers and thunderstorms, mainly before 3am. Low around 62. Southwest wind around 9 mph becoming northwest after midnight. Winds could gust as high as 20 mph. Chance of precipitation is 90%.

    Low: 62 °F

    T-storms then
    Chance
    T-storms

  • Monday

    Monday: Cloudy, then gradually becoming mostly sunny, with a high near 77. North wind around 9 mph.

    High: 77 °F

    Decreasing
    Clouds

  • Monday Night

    Monday Night: Partly cloudy, with a low around 60. North wind around 6 mph becoming calm in the evening.

    Low: 60 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 81.

    High: 81 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: A 20 percent chance of showers after 1am. Mostly clear, with a low around 62.

    Low: 62 °F

    Mostly Clear
    then Slight
    Chance
    Showers

  • Wednesday

    Wednesday: Mostly sunny, with a high near 84.

    High: 84 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 61.

    Low: 61 °F

    Partly Cloudy

Detailed Forecast

Overnight
Mostly cloudy, with a low around 68. East wind 3 to 6 mph.
Sunday
Showers and thunderstorms. High near 84. Southeast wind 8 to 13 mph becoming southwest in the afternoon. Winds could gust as high as 26 mph. Chance of precipitation is 80%.
Sunday Night
Showers and thunderstorms, mainly before 3am. Low around 62. Southwest wind around 9 mph becoming northwest after midnight. Winds could gust as high as 20 mph. Chance of precipitation is 90%.
Monday
Cloudy, then gradually becoming mostly sunny, with a high near 77. North wind around 9 mph.
Monday Night
Partly cloudy, with a low around 60. North wind around 6 mph becoming calm in the evening.
Tuesday
Mostly sunny, with a high near 81.
Tuesday Night
A 20 percent chance of showers after 1am. Mostly clear, with a low around 62.
Wednesday
Mostly sunny, with a high near 84.
Wednesday Night
Partly cloudy, with a low around 61.
Thursday
A slight chance of showers, with thunderstorms also possible after 1pm. Mostly sunny, with a high near 82. Chance of precipitation is 20%.
Thursday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 62.
Friday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 84.
Friday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 66.
Saturday
A 40 percent chance of showers and thunderstorms. Partly sunny, with a high near 86.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
O'Fallon MO
 38.81°N 90.71°W (Elev. 502 ft)
Last Update:
11:51 pm CDT Jun 20, 2026
Forecast Valid:
1am CDT Jun 21, 2026-6pm CDT Jun 27, 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