Thunderstorms and Heavy Rain in the Mid-South; Heat Continues in the Southeast and Southwest

Severe thunderstorms and heavy rain are expected across portions of the mid-Mississippi Valley into the Ohio Valley and portions of Arizona. Dangerous heat persists in the South and Southeast while building into the Southwest. Overnight lows will be so warm that, when combined with oppressive dew points, little-to-no relief from the scorching daytime highs will be available. Read More >

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Light Rain Fog/Mist

73°F

23°C

Humidity 96%
Wind Speed S 5 mph
Barometer 29.95 in (1013.6 mb)
Dewpoint 72°F (22°C)
Visibility 6.00 mi
Last update 19 Aug 5:53 am CDT
Extended Forecast for

O'Fallon IL

  • Today

    Today: Showers and possibly a thunderstorm before 10am, then scattered showers and thunderstorms, mainly between 10am and 1pm.  High near 81. West wind around 6 mph becoming south in the morning.  Chance of precipitation is 80%.

    High: 81 °F

    Showers then
    Scattered
    Showers

  • Tonight

    Tonight: Scattered showers and thunderstorms, mainly before midnight.  Mostly cloudy, with a low around 68. Light and variable wind.  Chance of precipitation is 30%.

    Low: 68 °F

    Scattered
    T-storms

  • Thursday

    Thursday: Mostly sunny, with a high near 84. Northeast wind 3 to 6 mph.

    High: 84 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 66. Northeast wind around 5 mph becoming calm  in the evening.

    Low: 66 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 86. Calm wind becoming southwest around 5 mph in the afternoon.

    High: 86 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 68.

    Low: 68 °F

    Mostly Clear

  • Saturday

    Saturday: A 20 percent chance of showers and thunderstorms before 1pm.  Mostly sunny, with a high near 86.

    High: 86 °F

    Slight Chance
    T-storms

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 66.

    Low: 66 °F

    Mostly Clear

  • Sunday

    Sunday: Mostly sunny, with a high near 83.

    High: 83 °F

    Mostly Sunny

Detailed Forecast

Today
Showers and possibly a thunderstorm before 10am, then scattered showers and thunderstorms, mainly between 10am and 1pm. High near 81. West wind around 6 mph becoming south in the morning. Chance of precipitation is 80%.
Tonight
Scattered showers and thunderstorms, mainly before midnight. Mostly cloudy, with a low around 68. Light and variable wind. Chance of precipitation is 30%.
Thursday
Mostly sunny, with a high near 84. Northeast wind 3 to 6 mph.
Thursday Night
Mostly clear, with a low around 66. Northeast wind around 5 mph becoming calm in the evening.
Friday
Sunny, with a high near 86. Calm wind becoming southwest around 5 mph in the afternoon.
Friday Night
Mostly clear, with a low around 68.
Saturday
A 20 percent chance of showers and thunderstorms before 1pm. Mostly sunny, with a high near 86.
Saturday Night
Mostly clear, with a low around 66.
Sunday
Mostly sunny, with a high near 83.
Sunday Night
A 20 percent chance of showers after 1am. Partly cloudy, with a low around 65.
Monday
Partly sunny, with a high near 84.
Monday Night
Partly cloudy, with a low around 67.
Tuesday
Mostly sunny, with a high near 87.
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ABOUT THIS FORECAST

 
Point Forecast:
O'Fallon IL
 38.59°N 89.95°W (Elev. 545 ft)
5:21 am CDT Aug 19, 2026
6am CDT Aug 19, 2026-6pm CDT Aug 25, 2026
 
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Additional Resources

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