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

Extreme Heat Lingers; Severe Thunderstorms for Portions of the Plains and Southeast; Heavy Rainfall Threats

Gusty winds and heavy rainfall may impact the Big Island of Hawaii as a nearby tropical system passes west of the islands. From the Southwest U.S., Rockies and across the Gulf Coast, heavy rainfall could lead to isolated flash flooding. Severe thunderstorms are expected for areas of the Plains, Gulf Coast and Southeast through Tuesday. Extreme heat lingers for the southern Plains and Southwest. Read More >

Current conditions at

St. Louis Downtown Airport (KCPS)

Lat: 38.56°NLon: 90.15°WElev: 410ft.

Fair

63°F

17°C

Humidity 87%
Wind Speed Calm
Barometer 30.08 in (1018.4 mb)
Dewpoint 59°F (15°C)
Visibility 10.00 mi
Last update 24 Aug 7:53 am CDT
Extended Forecast for

Swansea IL

  • Today

    Today: Sunny, with a high near 83. Calm wind becoming east around 5 mph in the afternoon.

    High: 83 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 63. East wind 3 to 5 mph.

    Low: 63 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 86. East wind 5 to 7 mph.

    High: 86 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 68. East wind around 5 mph becoming calm in the evening.

    Low: 68 °F

    Partly Cloudy

  • Wednesday

    Wednesday: A slight chance of showers, with thunderstorms also possible after 4pm. Mostly sunny, with a high near 89. Calm wind becoming southwest around 6 mph in the afternoon. Chance of precipitation is 20%.

    High: 89 °F

    Slight Chance
    Showers then
    Slight Chance
    T-storms

  • Wednesday Night

    Wednesday Night: A 30 percent chance of showers and thunderstorms before 1am. Mostly clear, with a low around 68.

    Low: 68 °F

    Chance
    Showers

  • Thursday

    Thursday: Sunny, with a high near 88.

    High: 88 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 65.

    Low: 65 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 88.

    High: 88 °F

    Sunny

Detailed Forecast

Today
Sunny, with a high near 83. Calm wind becoming east around 5 mph in the afternoon.
Tonight
Mostly clear, with a low around 63. East wind 3 to 5 mph.
Tuesday
Mostly sunny, with a high near 86. East wind 5 to 7 mph.
Tuesday Night
Partly cloudy, with a low around 68. East wind around 5 mph becoming calm in the evening.
Wednesday
A slight chance of showers, with thunderstorms also possible after 4pm. Mostly sunny, with a high near 89. Calm wind becoming southwest around 6 mph in the afternoon. Chance of precipitation is 20%.
Wednesday Night
A 30 percent chance of showers and thunderstorms before 1am. Mostly clear, with a low around 68.
Thursday
Sunny, with a high near 88.
Thursday Night
Mostly clear, with a low around 65.
Friday
Sunny, with a high near 88.
Friday Night
Mostly clear, with a low around 66.
Saturday
Mostly sunny, with a high near 90.
Saturday Night
A 20 percent chance of showers and thunderstorms. Partly cloudy, with a low around 71.
Sunday
Partly sunny, with a high near 93.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Swansea IL
 38.55°N 89.98°W (Elev. 551 ft)
Last Update:
5:41 am CDT Aug 24, 2026
Forecast Valid:
8am CDT Aug 24, 2026-6pm CDT Aug 30, 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