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

Hazardous Weather Conditions

Current conditions at

Mount Vernon Airport (KMVN)

Lat: 38.33°NLon: 88.85°WElev: 466ft.

Fair

78°F

26°C

Humidity 87%
Wind Speed SW 3 mph
Barometer 30.09 in (1018.7 mb)
Dewpoint 74°F (23°C)
Visibility 10.00 mi
Heat Index80°F (27°C)
Last update 15 Aug 6:56 am CDT
Extended Forecast for

Nason IL

Extreme Heat Warning August 15, 07:37am until August 16, 08:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning August 15, 07:37am until August 16, 08:00pm

    NOW until 8:00pm Sun

    Extreme Heat Warning

  • Today

    High: 97 °F

    Hot

  • Tonight

    Tonight: Clear, with a low around 77. Calm wind becoming southwest around 6 mph in the evening.

    Low: 77 °F

    Clear

  • Sunday

    Sunday: Mostly sunny and hot, with a high near 97. Heat index values as high as 111. West wind 3 to 7 mph.

    High: 97 °F

    Hot

  • Sunday Night

    Sunday Night: A chance of showers and thunderstorms. Partly cloudy, with a low around 73. North northwest wind around 5 mph becoming calm in the evening. Chance of precipitation is 50%.

    Low: 73 °F

    Chance
    T-storms

  • Monday

    Monday: Mostly sunny, with a high near 88. North wind 3 to 7 mph.

    High: 88 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 67. Light northeast wind.

    Low: 67 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Sunny, with a high near 90. Calm wind.

    High: 90 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 72. Calm wind becoming south 5 to 7 mph in the evening.

    Low: 72 °F

    Mostly Clear

Detailed Forecast

Today
Mostly sunny and hot, with a high near 97. Heat index values as high as 110. Calm wind becoming west northwest around 5 mph in the morning.
Tonight
Clear, with a low around 77. Calm wind becoming southwest around 6 mph in the evening.
Sunday
Mostly sunny and hot, with a high near 97. Heat index values as high as 111. West wind 3 to 7 mph.
Sunday Night
A chance of showers and thunderstorms. Partly cloudy, with a low around 73. North northwest wind around 5 mph becoming calm in the evening. Chance of precipitation is 50%.
Monday
Mostly sunny, with a high near 88. North wind 3 to 7 mph.
Monday Night
Partly cloudy, with a low around 67. Light northeast wind.
Tuesday
Sunny, with a high near 90. Calm wind.
Tuesday Night
Mostly clear, with a low around 72. Calm wind becoming south 5 to 7 mph in the evening.
Wednesday
A slight chance of showers and thunderstorms. Partly sunny, with a high near 94. South wind 6 to 13 mph becoming west northwest in the afternoon. Winds could gust as high as 18 mph.
Wednesday Night
A slight chance of showers and thunderstorms. Partly cloudy, with a low around 69. North wind 7 to 10 mph.
Thursday
A slight chance of showers and thunderstorms. Mostly sunny, with a high near 84. North northeast wind 5 to 7 mph.
Thursday Night
A chance of showers and thunderstorms. Partly cloudy, with a low around 63. East northeast wind 5 to 7 mph.
Friday
A slight chance of showers. Mostly sunny, with a high near 83. East northeast wind 5 to 7 mph.
Basemap Options
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Nason IL
 38.18°N 88.98°W
Last Update:
7:01 am CDT Aug 15, 2026
Forecast Valid:
7am CDT Aug 15, 2026-6pm CDT Aug 21, 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