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.

Overcast and Breezy

46°F

8°C

Humidity 79%
Wind Speed NW 21 G 29 mph
Barometer 30.05 in (1017.5 mb)
Dewpoint 40°F (4°C)
Visibility 10.00 mi
Wind Chill38°F (3°C)
Last update 11 Mar 5:52 pm CDT
Extended Forecast for

Saint Johns IL

  • Tonight

    Tonight: Cloudy during the early evening, then gradual clearing, with a low around 31. Blustery, with a north northwest wind 16 to 21 mph decreasing to 8 to 13 mph after midnight. Winds could gust as high as 31 mph.

    Low: 31 °F

    Mostly Cloudy
    and Blustery
    then Partly
    Cloudy

  • Thursday

    Thursday: Sunny, with a high near 54. Light and variable wind becoming west 5 to 8 mph in the morning.

    High: 54 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 41. South wind 9 to 18 mph, with gusts as high as 29 mph.

    Low: 41 °F

    Mostly Clear

  • Friday

    Friday: Partly sunny, with a high near 63. Southwest wind 10 to 15 mph, with gusts as high as 24 mph.

    High: 63 °F

    Partly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 36. Northwest wind around 6 mph becoming east northeast after midnight.

    Low: 36 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 63. East northeast wind 6 to 10 mph becoming southeast in the afternoon.

    High: 63 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly cloudy, with a low around 50. East southeast wind 7 to 13 mph, with gusts as high as 21 mph.

    Low: 50 °F

    Mostly Cloudy

  • Sunday

    Sunday: A chance of showers and thunderstorms, then showers likely after 1pm. Mostly cloudy, with a high near 69. Breezy, with a south wind 15 to 23 mph, with gusts as high as 33 mph.

    High: 69 °F

    Showers
    Likely and
    Breezy

  • Sunday Night

    Sunday Night: A chance of rain showers before 1am, then a slight chance of rain and snow showers. Mostly cloudy, with a low around 26. Breezy, with a west northwest wind 21 to 23 mph, with gusts as high as 33 mph.

    Low: 26 °F

    Chance
    Showers and
    Breezy then
    Chance
    Rain/Snow and
    Blustery

Detailed Forecast

Tonight
Cloudy during the early evening, then gradual clearing, with a low around 31. Blustery, with a north northwest wind 16 to 21 mph decreasing to 8 to 13 mph after midnight. Winds could gust as high as 31 mph.
Thursday
Sunny, with a high near 54. Light and variable wind becoming west 5 to 8 mph in the morning.
Thursday Night
Mostly clear, with a low around 41. South wind 9 to 18 mph, with gusts as high as 29 mph.
Friday
Partly sunny, with a high near 63. Southwest wind 10 to 15 mph, with gusts as high as 24 mph.
Friday Night
Partly cloudy, with a low around 36. Northwest wind around 6 mph becoming east northeast after midnight.
Saturday
Mostly sunny, with a high near 63. East northeast wind 6 to 10 mph becoming southeast in the afternoon.
Saturday Night
Mostly cloudy, with a low around 50. East southeast wind 7 to 13 mph, with gusts as high as 21 mph.
Sunday
A chance of showers and thunderstorms, then showers likely after 1pm. Mostly cloudy, with a high near 69. Breezy, with a south wind 15 to 23 mph, with gusts as high as 33 mph.
Sunday Night
A chance of rain showers before 1am, then a slight chance of rain and snow showers. Mostly cloudy, with a low around 26. Breezy, with a west northwest wind 21 to 23 mph, with gusts as high as 33 mph.
Monday
Mostly sunny, with a high near 38. Northwest wind 16 to 18 mph, with gusts as high as 26 mph.
Monday Night
Mostly clear, with a low around 18. North northwest wind 5 to 11 mph, with gusts as high as 18 mph.
Tuesday
Partly sunny, with a high near 42. North northwest wind 6 to 8 mph becoming south southwest in the afternoon.
Tuesday Night
A slight chance of rain and snow showers. Mostly cloudy, with a low around 31. South southeast wind around 7 mph.
Wednesday
Mostly cloudy, with a high near 55. Southwest wind 8 to 10 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:
1:26 pm CDT Mar 11, 2026
Forecast Valid:
5pm CDT Mar 11, 2026-6pm CDT Mar 18, 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