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.

Fair

28°F

-2°C

Humidity 60%
Wind Speed SE 9 mph
Barometer 30.33 in (1027.4 mb)
Dewpoint 16°F (-9°C)
Visibility 10.00 mi
Wind Chill19°F (-7°C)
Last update 7 Feb 8:52 pm CST
Extended Forecast for

Saint Johns IL

  • Tonight

    Tonight: Mostly cloudy, with a low around 26. Southeast wind around 7 mph.

    Low: 26 °F

    Mostly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 46. Southeast wind 6 to 9 mph.

    High: 46 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 29. East wind 3 to 7 mph.

    Low: 29 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 55. Light and variable wind.

    High: 55 °F

    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 39. South southwest wind 3 to 6 mph.

    Low: 39 °F

    Mostly Clear

  • Tuesday

    Tuesday: A 20 percent chance of showers after noon. Mostly sunny, with a high near 63. South southwest wind 6 to 8 mph becoming north northwest in the afternoon.

    High: 63 °F

    Mostly Sunny
    then Slight
    Chance
    Showers

  • Tuesday Night

    Tuesday Night: Showers likely. Mostly cloudy, with a low around 39. North wind around 7 mph. Chance of precipitation is 60%.

    Low: 39 °F

    Showers
    Likely

  • Wednesday

    Wednesday: A chance of showers, mainly before noon. Mostly cloudy, with a high near 49. Northeast wind 6 to 8 mph.

    High: 49 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: A slight chance of showers after midnight. Mostly cloudy, with a low around 36. East northeast wind around 6 mph.

    Low: 36 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

Detailed Forecast

Tonight
Mostly cloudy, with a low around 26. Southeast wind around 7 mph.
Sunday
Mostly sunny, with a high near 46. Southeast wind 6 to 9 mph.
Sunday Night
Mostly clear, with a low around 29. East wind 3 to 7 mph.
Monday
Sunny, with a high near 55. Light and variable wind.
Monday Night
Mostly clear, with a low around 39. South southwest wind 3 to 6 mph.
Tuesday
A 20 percent chance of showers after noon. Mostly sunny, with a high near 63. South southwest wind 6 to 8 mph becoming north northwest in the afternoon.
Tuesday Night
Showers likely. Mostly cloudy, with a low around 39. North wind around 7 mph. Chance of precipitation is 60%.
Wednesday
A chance of showers, mainly before noon. Mostly cloudy, with a high near 49. Northeast wind 6 to 8 mph.
Wednesday Night
A slight chance of showers after midnight. Mostly cloudy, with a low around 36. East northeast wind around 6 mph.
Thursday
A chance of showers, mainly after noon. Mostly cloudy, with a high near 46. East northeast wind 6 to 8 mph.
Thursday Night
A chance of showers. Mostly cloudy, with a low around 31. Northeast wind around 6 mph.
Friday
A slight chance of showers. Partly sunny, with a high near 47. Northeast wind 6 to 8 mph.
Friday Night
A chance of showers. Mostly cloudy, with a low around 29. East northeast wind around 7 mph.
Saturday
A chance of rain and snow showers. Partly sunny, with a high near 43. East northeast wind 8 to 10 mph.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Saint Johns IL
 38.03°N 89.24°W
Last Update:
6:22 pm CST Feb 7, 2026
Forecast Valid:
9pm CST Feb 7, 2026-6pm CST Feb 14, 2026
 
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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