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Hazardous Weather Conditions

Current conditions at

Southern Illinois Airport (KMDH)

Lat: 37.78°NLon: 89.25°WElev: 400ft.

Fog/Mist

73°F

23°C

Humidity 96%
Wind Speed Calm
Barometer 30.01 in (1015.7 mb)
Dewpoint 72°F (22°C)
Visibility 6.00 mi
Last update 19 Aug 3:52 am CDT
Extended Forecast for

3 Miles WSW Saint Johns IL

Heat Advisory August 19, 04:36am until August 19, 07:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory August 19, 04:36am until August 19, 07:00pm

    NOW until 7:00pm Tue

    Heat Advisory

  • Today

    High: 98 °F

    Sunny then
    Slight Chance
    T-storms

  • Tonight

    Tonight: A 40 percent chance of showers and thunderstorms, mainly before 10pm. Partly cloudy, with a low around 72. North wind 3 to 6 mph.

    Low: 72 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: Mostly sunny, with a high near 90. North wind 6 to 11 mph.

    High: 90 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 66. North northeast wind 6 to 10 mph.

    Low: 66 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 88. North northeast wind 6 to 10 mph.

    High: 88 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 65. North northeast wind 5 to 8 mph becoming calm in the evening.

    Low: 65 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 90. Calm wind becoming north northeast 5 to 7 mph in the morning.

    High: 90 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 65. North wind around 6 mph becoming calm in the evening.

    Low: 65 °F

    Mostly Clear

Detailed Forecast

Today
A 20 percent chance of showers and thunderstorms after 1pm. Sunny and hot, with a high near 98. Heat index values as high as 106. Calm wind becoming northwest 5 to 7 mph in the morning.
Tonight
A 40 percent chance of showers and thunderstorms, mainly before 10pm. Partly cloudy, with a low around 72. North wind 3 to 6 mph.
Wednesday
Mostly sunny, with a high near 90. North wind 6 to 11 mph.
Wednesday Night
Partly cloudy, with a low around 66. North northeast wind 6 to 10 mph.
Thursday
Mostly sunny, with a high near 88. North northeast wind 6 to 10 mph.
Thursday Night
Mostly clear, with a low around 65. North northeast wind 5 to 8 mph becoming calm in the evening.
Friday
Sunny, with a high near 90. Calm wind becoming north northeast 5 to 7 mph in the morning.
Friday Night
Mostly clear, with a low around 65. North wind around 6 mph becoming calm in the evening.
Saturday
Sunny, with a high near 91. Calm wind becoming north 5 to 8 mph in the afternoon.
Saturday Night
Mostly clear, with a low around 62. North wind 3 to 6 mph.
Sunday
Sunny, with a high near 86. Light north northwest wind increasing to 5 to 10 mph in the morning.
Sunday Night
Mostly clear, with a low around 58. North wind 5 to 7 mph becoming calm after midnight.
Monday
Sunny, with a high near 81. Calm wind becoming north northwest 5 to 8 mph in the morning.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
3 Miles WSW Saint Johns IL
 38.01°N 89.27°W
Last Update:
4:30 am CDT Aug 19, 2025
Forecast Valid:
4am CDT Aug 19, 2025-6pm CDT Aug 25, 2025
 
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