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.

Mostly Cloudy

82°F

28°C

Humidity 70%
Wind Speed NE 14 mph
Barometer 30.11 in
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index86°F (30°C)
Last update 12 Jul 12:45 pm CDT
Extended Forecast for

Johnston City IL

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 86. North northeast wind around 10 mph.

    High: 86 °F

    Mostly Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 68. North northeast wind 3 to 7 mph.

    Low: 68 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 87. North northeast wind 5 to 11 mph.

    High: 87 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 69. North northeast wind 3 to 6 mph.

    Low: 69 °F

    Mostly Clear

  • Tuesday

    Tuesday: A 20 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 89. Light northeast wind becoming east northeast 5 to 9 mph in the morning.

    High: 89 °F

    Sunny then
    Slight Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 70. Light and variable wind.

    Low: 70 °F

    Mostly Clear

  • Wednesday

    Wednesday: A 30 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 91. Light and variable wind.

    High: 91 °F

    Sunny then
    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 72. Calm wind.

    Low: 72 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 92. Light and variable wind.

    High: 92 °F

    Sunny

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 86. North northeast wind around 10 mph.
Tonight
Mostly clear, with a low around 68. North northeast wind 3 to 7 mph.
Monday
Sunny, with a high near 87. North northeast wind 5 to 11 mph.
Monday Night
Mostly clear, with a low around 69. North northeast wind 3 to 6 mph.
Tuesday
A 20 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 89. Light northeast wind becoming east northeast 5 to 9 mph in the morning.
Tuesday Night
Mostly clear, with a low around 70. Light and variable wind.
Wednesday
A 30 percent chance of showers and thunderstorms after 1pm. Sunny, with a high near 91. Light and variable wind.
Wednesday Night
Mostly clear, with a low around 72. Calm wind.
Thursday
Sunny, with a high near 92. Light and variable wind.
Thursday Night
Mostly clear, with a low around 73. Calm wind.
Friday
Sunny, with a high near 93. Calm wind becoming west 5 to 7 mph in the morning.
Friday Night
Mostly clear, with a low around 73. Light south wind.
Saturday
Mostly sunny, with a high near 93. West southwest wind 5 to 8 mph.
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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:
12:46 pm CDT Jul 12, 2026
Forecast Valid:
1pm CDT Jul 12, 2026-6pm CDT Jul 18, 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