National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce
Current conditions at

Southern Illinois Airport (KMDH)

Lat: 37.78°NLon: 89.25°WElev: 400ft.

Overcast

28°F

-2°C

Humidity 69%
Wind Speed SW 5 mph
Barometer 30.24 in (1024.4 mb)
Dewpoint 19°F (-7°C)
Visibility 10.00 mi
Wind Chill22°F (-6°C)
Last update 2 Feb 8:52 am CST
Extended Forecast for

Saint Johns IL

  • Today

    Today: Partly sunny, with a high near 37. Light and variable wind becoming west southwest around 5 mph.

    High: 37 °F

    Partly Sunny

  • Tonight

    Tonight: Mostly cloudy, with a low around 27. Light east wind.

    Low: 27 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: A chance of freezing rain before 10am, then a chance of rain between 10am and 3pm, then a chance of rain and snow after 3pm. Mostly cloudy, with a high near 36. Calm wind becoming north 5 to 8 mph in the morning. Chance of precipitation is 30%.

    High: 36 °F

    Chance Wintry
    Mix

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 19. North wind 5 to 7 mph.

    Low: 19 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Partly sunny, with a high near 30. North wind 3 to 6 mph.

    High: 30 °F

    Partly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 14. Calm wind.

    Low: 14 °F

    Partly Cloudy

  • Thursday

    Thursday: Mostly sunny, with a high near 36. Calm wind becoming south 5 to 8 mph in the morning.

    High: 36 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 29. South wind around 9 mph becoming west after midnight.

    Low: 29 °F

    Mostly Clear

  • Friday

    Friday: Mostly sunny, with a high near 46. West wind 7 to 10 mph becoming north northwest in the afternoon.

    High: 46 °F

    Mostly Sunny

Detailed Forecast

Today
Partly sunny, with a high near 37. Light and variable wind becoming west southwest around 5 mph.
Tonight
Mostly cloudy, with a low around 27. Light east wind.
Tuesday
A chance of freezing rain before 10am, then a chance of rain between 10am and 3pm, then a chance of rain and snow after 3pm. Mostly cloudy, with a high near 36. Calm wind becoming north 5 to 8 mph in the morning. Chance of precipitation is 30%.
Tuesday Night
Mostly cloudy, with a low around 19. North wind 5 to 7 mph.
Wednesday
Partly sunny, with a high near 30. North wind 3 to 6 mph.
Wednesday Night
Partly cloudy, with a low around 14. Calm wind.
Thursday
Mostly sunny, with a high near 36. Calm wind becoming south 5 to 8 mph in the morning.
Thursday Night
Mostly clear, with a low around 29. South wind around 9 mph becoming west after midnight.
Friday
Mostly sunny, with a high near 46. West wind 7 to 10 mph becoming north northwest in the afternoon.
Friday Night
Partly cloudy, with a low around 21. North northwest wind around 6 mph.
Saturday
Sunny, with a high near 37. North northeast wind 5 to 7 mph becoming east in the afternoon.
Saturday Night
Partly cloudy, with a low around 22. East southeast wind around 6 mph.
Sunday
Mostly sunny, with a high near 41. South southeast wind 5 to 7 mph.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Saint Johns IL
 38.03°N 89.24°W
Last Update:
6:26 am CST Feb 2, 2026
Forecast Valid:
9am CST Feb 2, 2026-6pm CST Feb 8, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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