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

Hazardous Weather Conditions

Current conditions at

Southern Illinois Airport (KMDH)

Lat: 37.78°NLon: 89.25°WElev: 400ft.

Fair

91°F

33°C

Humidity 59%
Wind Speed SE 7 mph
Barometer 30.07 in
Dewpoint 75°F (24°C)
Visibility 10.00 mi
Heat Index102°F (39°C)
Last update 14 Aug 12:52 pm CDT
Extended Forecast for

Vergennes IL

Extreme Heat Warning August 14, 01:30pm until August 16, 08:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning August 14, 01:30pm until August 16, 08:00pm

    NOW until 8:00pm Sun

    Extreme Heat Warning

  • This Afternoon

    High: 94 °F

    Sunny

  • Tonight

    Tonight: Clear, with a low around 74. Light south wind.

    Low: 74 °F

    Clear

  • Saturday

    Saturday: Sunny and hot, with a high near 99. Heat index values as high as 111. Southwest wind 3 to 5 mph.

    High: 99 °F

    Hot

  • Saturday Night

    Saturday Night: Clear, with a low around 74. South southwest wind 3 to 6 mph.

    Low: 74 °F

    Clear

  • Sunday

    Sunday: Sunny and hot, with a high near 98. West northwest wind around 6 mph.

    High: 98 °F

    Hot

  • Sunday Night

    Sunday Night: A 40 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 72. Light north wind.

    Low: 72 °F

    Slight Chance
    T-storms then
    Chance
    Showers

  • Monday

    Monday: A 30 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 89. North northwest wind 3 to 7 mph.

    High: 89 °F

    Partly Sunny
    then Chance
    T-storms

  • Monday Night

    Monday Night: Partly cloudy, with a low around 67. North wind around 5 mph becoming calm in the evening.

    Low: 67 °F

    Partly Cloudy

Detailed Forecast

This Afternoon
Sunny, with a high near 94. Heat index values as high as 109. Calm wind becoming south 5 to 8 mph.
Tonight
Clear, with a low around 74. Light south wind.
Saturday
Sunny and hot, with a high near 99. Heat index values as high as 111. Southwest wind 3 to 5 mph.
Saturday Night
Clear, with a low around 74. South southwest wind 3 to 6 mph.
Sunday
Sunny and hot, with a high near 98. West northwest wind around 6 mph.
Sunday Night
A 40 percent chance of showers and thunderstorms, mainly after 1am. Partly cloudy, with a low around 72. Light north wind.
Monday
A 30 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 89. North northwest wind 3 to 7 mph.
Monday Night
Partly cloudy, with a low around 67. North wind around 5 mph becoming calm in the evening.
Tuesday
Mostly sunny, with a high near 90. Calm wind.
Tuesday Night
Mostly clear, with a low around 71. Calm wind becoming south around 5 mph after midnight.
Wednesday
Mostly sunny, with a high near 95. South southwest wind 5 to 10 mph becoming west in the afternoon.
Wednesday Night
A slight chance of showers and thunderstorms. Partly cloudy, with a low around 70. North wind 5 to 7 mph.
Thursday
A chance of showers and thunderstorms. Partly sunny, with a high near 87. North wind 5 to 8 mph.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Vergennes IL
 37.9°N 89.33°W
Last Update:
1:26 pm CDT Aug 14, 2026
Forecast Valid:
1pm CDT Aug 14, 2026-6pm CDT Aug 20, 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