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.

Light Drizzle Fog/Mist

59°F

15°C

Humidity 88%
Wind Speed NW 9 mph
Barometer 30.07 in
Dewpoint 55°F (13°C)
Visibility 4.00 mi
Last update 16 Oct 3:35 am CDT
Extended Forecast for

Johnston City IL

  • Overnight

    Overnight: A 30 percent chance of showers, mainly after 5am. Mostly cloudy, with a low around 49. Northwest wind around 16 mph, with gusts as high as 30 mph.

    Low: 49 °F

    Chance
    Showers

  • Friday

    Friday: Mostly cloudy, with a high near 56. Breezy, with a northwest wind 15 to 20 mph, with gusts as high as 29 mph.

    High: 56 °F

    Mostly Cloudy
    then Partly
    Sunny and
    Breezy

  • Friday Night

    Friday Night: Mostly cloudy, then gradually becoming mostly clear, with a low around 41. North wind 13 to 18 mph, with gusts as high as 24 mph.

    Low: 41 °F

    Decreasing
    Clouds

  • Saturday

    Saturday: Sunny, with a high near 61. North northeast wind 9 to 11 mph.

    High: 61 °F

    Sunny

  • Saturday Night

    Saturday Night: Patchy frost after 4am. Otherwise, clear, with a low around 35. Calm wind.

    Low: 35 °F

    Clear then
    Patchy Frost

  • Sunday

    Sunday: Areas of frost before 9am. Otherwise, sunny, with a high near 66. Calm wind becoming southeast around 6 mph in the morning.

    High: 66 °F

    Areas Frost
    then Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 38. Calm wind.

    Low: 38 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 71. Calm wind becoming south around 5 mph in the afternoon.

    High: 71 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 43. Calm wind.

    Low: 43 °F

    Mostly Clear

Detailed Forecast

Overnight
A 30 percent chance of showers, mainly after 5am. Mostly cloudy, with a low around 49. Northwest wind around 16 mph, with gusts as high as 30 mph.
Friday
Mostly cloudy, with a high near 56. Breezy, with a northwest wind 15 to 20 mph, with gusts as high as 29 mph.
Friday Night
Mostly cloudy, then gradually becoming mostly clear, with a low around 41. North wind 13 to 18 mph, with gusts as high as 24 mph.
Saturday
Sunny, with a high near 61. North northeast wind 9 to 11 mph.
Saturday Night
Patchy frost after 4am. Otherwise, clear, with a low around 35. Calm wind.
Sunday
Areas of frost before 9am. Otherwise, sunny, with a high near 66. Calm wind becoming southeast around 6 mph in the morning.
Sunday Night
Mostly clear, with a low around 38. Calm wind.
Monday
Sunny, with a high near 71. Calm wind becoming south around 5 mph in the afternoon.
Monday Night
Mostly clear, with a low around 43. Calm wind.
Tuesday
Sunny, with a high near 75. Calm wind becoming east around 5 mph in the afternoon.
Tuesday Night
Mostly clear, with a low around 45. Calm wind.
Wednesday
Sunny, with a high near 77. Calm wind becoming east around 5 mph in the afternoon.
Wednesday Night
Mostly clear, with a low around 47. Calm wind.
Thursday
Sunny, with a high near 80. Calm wind becoming south around 5 mph in the afternoon.
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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:
2:01 am CDT Oct 16, 2026
Forecast Valid:
3am CDT Oct 16, 2026-6pm CDT Oct 22, 2026
 
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Additional Resources

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Chance of Precipitation