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

Marion - Williamson County Regional Airport (KMWA)

Lat: 37.77°NLon: 89.01°WElev: 486ft.

Fair

76°F

24°C

Humidity 63%
Wind Speed Calm
Barometer 30.00 in
Dewpoint 62°F (17°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 27 Aug 7:15 pm CDT
Extended Forecast for

Johnston City IL

  • Tonight

    Tonight: Mostly clear, with a low around 64. North northwest wind around 6 mph becoming calm in the evening.

    Low: 64 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 88. Calm wind becoming north northeast 5 to 7 mph in the afternoon.

    High: 88 °F

    Sunny

  • Friday Night

    Friday Night: Clear, with a low around 62. Light north wind.

    Low: 62 °F

    Clear

  • Saturday

    Saturday: Sunny, with a high near 90. Calm wind becoming south southeast around 5 mph in the afternoon.

    High: 90 °F

    Sunny

  • Saturday Night

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

    Low: 66 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 95. Light south southeast wind becoming south southwest 5 to 10 mph in the morning.

    High: 95 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 72. South wind 3 to 6 mph.

    Low: 72 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 96. South southwest wind 6 to 11 mph.

    High: 96 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 74. South wind 3 to 7 mph.

    Low: 74 °F

    Mostly Clear

Detailed Forecast

Tonight
Mostly clear, with a low around 64. North northwest wind around 6 mph becoming calm in the evening.
Friday
Sunny, with a high near 88. Calm wind becoming north northeast 5 to 7 mph in the afternoon.
Friday Night
Clear, with a low around 62. Light north wind.
Saturday
Sunny, with a high near 90. Calm wind becoming south southeast around 5 mph in the afternoon.
Saturday Night
Mostly clear, with a low around 66. Calm wind.
Sunday
Sunny, with a high near 95. Light south southeast wind becoming south southwest 5 to 10 mph in the morning.
Sunday Night
Mostly clear, with a low around 72. South wind 3 to 6 mph.
Monday
Sunny, with a high near 96. South southwest wind 6 to 11 mph.
Monday Night
Mostly clear, with a low around 74. South wind 3 to 7 mph.
Tuesday
Sunny and hot, with a high near 97. Light south southwest wind becoming southwest 5 to 10 mph in the morning.
Tuesday Night
Mostly clear, with a low around 75. South wind 3 to 7 mph.
Wednesday
Sunny and hot, with a high near 97. Light south southwest wind becoming southwest 5 to 9 mph in the morning.
Wednesday Night
Mostly clear, with a low around 76. South southwest wind 3 to 6 mph.
Thursday
Sunny and hot, with a high near 98. Light south southwest wind becoming southwest 5 to 9 mph in the morning.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Johnston City IL
 37.82°N 88.94°W
Last Update:
4:16 pm CDT Aug 27, 2026
Forecast Valid:
7pm CDT Aug 27, 2026-6pm CDT Sep 3, 2026
 
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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