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

65°F

18°C

Humidity 98%
Wind Speed Calm
Barometer 30.04 in
Dewpoint 65°F (18°C)
Visibility 10.00 mi
Last update 23 Aug 2:15 am CDT
Extended Forecast for

Johnston City IL

  • Overnight

    Overnight: Patchy fog after 4am. Otherwise, clear, with a low around 63. Calm wind.

    Low: 63 °F

    Patchy Fog

  • Sunday

    Sunday: Patchy fog before 8am. Otherwise, sunny, with a high near 84. Calm wind becoming north northwest 5 to 8 mph in the afternoon.

    High: 84 °F

    Patchy Fog
    then Mostly
    Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 60. Light north wind.

    Low: 60 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 85. Light and variable wind.

    High: 85 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 62. Light east wind.

    Low: 62 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Sunny, with a high near 87. Calm wind becoming east southeast around 5 mph in the afternoon.

    High: 87 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 65. Light east wind.

    Low: 65 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 90. Calm wind becoming south southwest around 5 mph in the afternoon.

    High: 90 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 68. Calm wind.

    Low: 68 °F

    Mostly Clear

Detailed Forecast

Overnight
Patchy fog after 4am. Otherwise, clear, with a low around 63. Calm wind.
Sunday
Patchy fog before 8am. Otherwise, sunny, with a high near 84. Calm wind becoming north northwest 5 to 8 mph in the afternoon.
Sunday Night
Partly cloudy, with a low around 60. Light north wind.
Monday
Mostly sunny, with a high near 85. Light and variable wind.
Monday Night
Partly cloudy, with a low around 62. Light east wind.
Tuesday
Sunny, with a high near 87. Calm wind becoming east southeast around 5 mph in the afternoon.
Tuesday Night
Partly cloudy, with a low around 65. Light east wind.
Wednesday
Mostly sunny, with a high near 90. Calm wind becoming south southwest around 5 mph in the afternoon.
Wednesday Night
Mostly clear, with a low around 68. Calm wind.
Thursday
Sunny, with a high near 89. Light west wind becoming northwest 5 to 10 mph in the morning.
Thursday Night
Mostly clear, with a low around 66. North northwest wind around 6 mph becoming calm in the evening.
Friday
Sunny, with a high near 88. Calm wind becoming north northwest 5 to 7 mph in the afternoon.
Friday Night
Mostly clear, with a low around 65. North northeast wind around 5 mph becoming calm in the evening.
Saturday
Sunny, with a high near 89. Calm wind becoming south southwest 5 to 7 mph in the afternoon.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Johnston City IL
 37.82°N 88.91°W
Last Update:
1:26 am CDT Aug 23, 2026
Forecast Valid:
2am CDT Aug 23, 2026-6pm CDT Aug 29, 2026
 
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Additional Resources

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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