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

55°F

13°C

Humidity 96%
Wind Speed Calm
Barometer 30.09 in
Dewpoint 54°F (12°C)
Visibility 10.00 mi
Last update 25 Aug 3:35 am CDT
Extended Forecast for

Johnston City IL

  • Overnight

    Overnight: Clear, with a low around 54. Calm wind.

    Low: 54 °F

    Clear

  • Monday

    Monday: Increasing clouds, with a high near 78. Calm wind becoming north northwest 5 to 9 mph in the morning.

    High: 78 °F

    Increasing
    Clouds

  • Monday Night

    Monday Night: Mostly cloudy, then gradually becoming clear, with a low around 51. North northwest wind around 5 mph becoming calm in the evening.

    Low: 51 °F

    Decreasing
    Clouds

  • Tuesday

    Tuesday: Sunny, with a high near 79. Calm wind becoming north northwest 5 to 8 mph in the afternoon.

    High: 79 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Clear, with a low around 51. North wind around 6 mph becoming calm in the evening.

    Low: 51 °F

    Clear

  • Wednesday

    Wednesday: Mostly sunny, with a high near 80. Calm wind.

    High: 80 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 57. Calm wind.

    Low: 57 °F

    Mostly Cloudy

  • Thursday

    Thursday: A slight chance of showers. Partly sunny, with a high near 81. Calm wind becoming southwest around 5 mph.

    High: 81 °F

    Slight Chance
    Showers

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 57. Calm wind.

    Low: 57 °F

    Partly Cloudy

Detailed Forecast

Overnight
Clear, with a low around 54. Calm wind.
Monday
Increasing clouds, with a high near 78. Calm wind becoming north northwest 5 to 9 mph in the morning.
Monday Night
Mostly cloudy, then gradually becoming clear, with a low around 51. North northwest wind around 5 mph becoming calm in the evening.
Tuesday
Sunny, with a high near 79. Calm wind becoming north northwest 5 to 8 mph in the afternoon.
Tuesday Night
Clear, with a low around 51. North wind around 6 mph becoming calm in the evening.
Wednesday
Mostly sunny, with a high near 80. Calm wind.
Wednesday Night
Mostly cloudy, with a low around 57. Calm wind.
Thursday
A slight chance of showers. Partly sunny, with a high near 81. Calm wind becoming southwest around 5 mph.
Thursday Night
Partly cloudy, with a low around 57. Calm wind.
Friday
Sunny, with a high near 83. Northeast wind 3 to 8 mph.
Friday Night
Partly cloudy, with a low around 59. East northeast wind 3 to 6 mph.
Saturday
Mostly sunny, with a high near 81. East wind 5 to 8 mph.
Saturday Night
Partly cloudy, with a low around 59. East northeast wind 3 to 6 mph.
Sunday
A slight chance of showers. Mostly sunny, with a high near 79. East wind 5 to 7 mph.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Johnston City IL
 37.82°N 88.91°W
Last Update:
3:01 am CDT Aug 25, 2025
Forecast Valid:
3am CDT Aug 25, 2025-6pm CDT Aug 31, 2025
 
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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