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

Hazardous Weather Conditions

Current conditions at

Marion - Williamson County Regional Airport (KMWA)

Lat: 37.77°NLon: 89.01°WElev: 486ft.

Partly Cloudy

86°F

30°C

Humidity 59%
Wind Speed S 9 mph
Barometer 30.05 in
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Heat Index91°F (33°C)
Last update 20 Jun 12:45 pm CDT
Extended Forecast for

Johnston City IL

Heat Advisory June 21, 12:00pm until June 24, 07:00pm
Click here for hazard details and duration
Heat Advisory

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 90. South southwest wind around 9 mph.

    High: 90 °F

    Mostly Sunny

  • Tonight

    Tonight: Clear, with a low around 75. South wind around 7 mph.

    Low: 75 °F

    Clear

  • Saturday

    Saturday: Sunny, with a high near 94. Heat index values as high as 106. South southwest wind 7 to 13 mph, with gusts as high as 20 mph.

    High: 94 °F

    Sunny

  • Saturday Night

    Saturday Night: Clear, with a low around 77. South wind 6 to 9 mph.

    Low: 77 °F

    Clear

  • Sunday

    Sunday: Sunny, with a high near 95. South southwest wind 6 to 9 mph.

    High: 95 °F

    Sunny

  • Sunday Night

    Sunday Night: Clear, with a low around 76. South wind 3 to 6 mph.

    Low: 76 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 94. South wind 3 to 6 mph.

    High: 94 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 76. South wind around 5 mph becoming calm in the evening.

    Low: 76 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 94. Light south southwest wind.

    High: 94 °F

    Sunny

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 90. South southwest wind around 9 mph.
Tonight
Clear, with a low around 75. South wind around 7 mph.
Saturday
Sunny, with a high near 94. Heat index values as high as 106. South southwest wind 7 to 13 mph, with gusts as high as 20 mph.
Saturday Night
Clear, with a low around 77. South wind 6 to 9 mph.
Sunday
Sunny, with a high near 95. South southwest wind 6 to 9 mph.
Sunday Night
Clear, with a low around 76. South wind 3 to 6 mph.
Monday
Sunny, with a high near 94. South wind 3 to 6 mph.
Monday Night
Mostly clear, with a low around 76. South wind around 5 mph becoming calm in the evening.
Tuesday
Sunny, with a high near 94. Light south southwest wind.
Tuesday Night
Mostly clear, with a low around 76. Calm wind.
Wednesday
Sunny, with a high near 94. Calm wind becoming south southwest around 5 mph in the afternoon.
Wednesday Night
Mostly clear, with a low around 76. Light south southwest wind.
Thursday
A slight chance of showers and thunderstorms. Sunny, with a high near 93. Calm wind becoming south southwest around 6 mph in the morning.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Johnston City IL
 37.82°N 88.91°W
Last Update:
11:31 am CDT Jun 20, 2025
Forecast Valid:
12pm CDT Jun 20, 2025-6pm CDT Jun 26, 2025
 
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