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

Hazardous Weather Conditions

Current conditions at

Southern Illinois Airport (KMDH)

Lat: 37.78°NLon: 89.25°WElev: 400ft.

Light Rain Fog/Mist

61°F

16°C

Humidity 93%
Wind Speed SW 8 mph
Barometer 30.01 in (1016.0 mb)
Dewpoint 59°F (15°C)
Visibility 5.00 mi
Last update 7 Mar 10:52 am CST
Extended Forecast for

Saint Johns IL

  • Today

    Today: Showers and thunderstorms likely before 4pm, then a slight chance of showers between 4pm and 5pm. Mostly cloudy, with a temperature falling to around 58 by 5pm. West northwest wind 10 to 14 mph, with gusts as high as 22 mph. Chance of precipitation is 60%.

    High: 66 °F⇓

    Showers
    Likely

  • Tonight

    Tonight: Mostly cloudy, then gradually becoming mostly clear, with a low around 38. West northwest wind 6 to 11 mph becoming light northwest after midnight. Winds could gust as high as 18 mph.

    Low: 38 °F

    Decreasing
    Clouds

  • Sunday

    Sunday: Sunny, with a high near 65. Calm wind becoming southwest 5 to 7 mph in the morning.

    High: 65 °F

    Sunny

  • Sunday Night

    Sunday Night: Clear, with a low around 45. South wind around 7 mph.

    Low: 45 °F

    Clear

  • Monday

    Monday: Sunny, with a high near 74. South southwest wind 7 to 15 mph, with gusts as high as 23 mph.

    High: 74 °F

    Sunny

  • Monday Night

    Monday Night: A 20 percent chance of showers after midnight. Partly cloudy, with a low around 61. South southwest wind 9 to 14 mph, with gusts as high as 22 mph.

    Low: 61 °F

    Mostly Clear
    then Slight
    Chance
    Showers

  • Tuesday

    Tuesday: A slight chance of showers, then a chance of showers and thunderstorms after noon. Mostly cloudy, with a high near 79. South southwest wind 9 to 16 mph, with gusts as high as 24 mph. Chance of precipitation is 40%.

    High: 79 °F

    Slight Chance
    Showers then
    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Showers and possibly a thunderstorm. Cloudy, with a low around 63. South wind 15 to 17 mph, with gusts as high as 28 mph.

    Low: 63 °F

    Showers

  • Wednesday

    Wednesday: Showers and possibly a thunderstorm. Cloudy, with a high near 71. South southwest wind 16 to 18 mph becoming northwest in the afternoon. Winds could gust as high as 28 mph.

    High: 71 °F

    Showers

Detailed Forecast

Today
Showers and thunderstorms likely before 4pm, then a slight chance of showers between 4pm and 5pm. Mostly cloudy, with a temperature falling to around 58 by 5pm. West northwest wind 10 to 14 mph, with gusts as high as 22 mph. Chance of precipitation is 60%.
Tonight
Mostly cloudy, then gradually becoming mostly clear, with a low around 38. West northwest wind 6 to 11 mph becoming light northwest after midnight. Winds could gust as high as 18 mph.
Sunday
Sunny, with a high near 65. Calm wind becoming southwest 5 to 7 mph in the morning.
Sunday Night
Clear, with a low around 45. South wind around 7 mph.
Monday
Sunny, with a high near 74. South southwest wind 7 to 15 mph, with gusts as high as 23 mph.
Monday Night
A 20 percent chance of showers after midnight. Partly cloudy, with a low around 61. South southwest wind 9 to 14 mph, with gusts as high as 22 mph.
Tuesday
A slight chance of showers, then a chance of showers and thunderstorms after noon. Mostly cloudy, with a high near 79. South southwest wind 9 to 16 mph, with gusts as high as 24 mph. Chance of precipitation is 40%.
Tuesday Night
Showers and possibly a thunderstorm. Cloudy, with a low around 63. South wind 15 to 17 mph, with gusts as high as 28 mph.
Wednesday
Showers and possibly a thunderstorm. Cloudy, with a high near 71. South southwest wind 16 to 18 mph becoming northwest in the afternoon. Winds could gust as high as 28 mph.
Wednesday Night
A chance of showers before midnight. Partly cloudy, with a low around 34. Northwest wind 10 to 18 mph, with gusts as high as 26 mph.
Thursday
Sunny, with a high near 51. Northwest wind 6 to 10 mph.
Thursday Night
Mostly cloudy, with a low around 37. South wind 5 to 13 mph, with gusts as high as 22 mph.
Friday
Partly sunny, with a high near 64. Southwest wind 13 to 17 mph, with gusts as high as 25 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:
11:12 am CST Mar 7, 2026
Forecast Valid:
11am CST Mar 7, 2026-6pm CDT Mar 13, 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