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.

Fog/Mist

56°F

13°C

Humidity 97%
Wind Speed N 5 mph
Barometer 30.08 in (1018.4 mb)
Dewpoint 55°F (13°C)
Visibility 6.00 mi
Last update 4 Mar 4:52 am CST
Extended Forecast for

Saint Johns IL

  • Overnight

    Overnight: A 50 percent chance of showers and thunderstorms. Cloudy, with a low around 54. Light east wind.

    Low: 54 °F

    Chance
    Showers

  • Wednesday

    Wednesday: Showers and thunderstorms likely, then showers and possibly a thunderstorm after 2pm. High near 70. Light and variable wind becoming south southwest 5 to 10 mph in the morning. Chance of precipitation is 90%.

    High: 70 °F

    Showers
    Likely then
    Showers

  • Wednesday Night

    Wednesday Night: Showers and thunderstorms before midnight, then showers and possibly a thunderstorm, mainly after midnight. Low around 57. South wind 6 to 8 mph. Chance of precipitation is 100%.

    Low: 57 °F

    Showers then
    T-storms

  • Thursday

    Thursday: Showers and possibly a thunderstorm before noon, then a chance of showers between noon and 3pm, then a chance of showers and thunderstorms after 3pm. High near 71. Southwest wind 7 to 11 mph. Chance of precipitation is 90%.

    High: 71 °F

    Showers then
    Chance
    Showers

  • Thursday Night

    Thursday Night: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 59. South wind 5 to 8 mph.

    Low: 59 °F

    Chance
    Showers

  • Friday

    Friday: A 30 percent chance of showers, mainly before noon. Partly sunny, with a high near 77. South wind 9 to 18 mph, with gusts as high as 26 mph.

    High: 77 °F

    Chance
    Showers

  • Friday Night

    Friday Night: A chance of showers before 9pm, then a chance of showers and thunderstorms between 9pm and midnight, then showers and possibly a thunderstorm after midnight. Low around 57. South wind 11 to 14 mph, with gusts as high as 23 mph. Chance of precipitation is 80%.

    Low: 57 °F

    Chance
    Showers then
    Showers

  • Saturday

    Saturday: Showers likely, mainly before noon. Mostly cloudy, with a high near 67. Southwest wind 7 to 13 mph becoming northwest in the afternoon. Winds could gust as high as 21 mph.

    High: 67 °F

    Showers
    Likely

  • Saturday Night

    Saturday Night: A slight chance of showers before midnight. Partly cloudy, with a low around 41. Northwest wind around 6 mph becoming calm in the evening.

    Low: 41 °F

    Slight Chance
    Showers then
    Mostly Clear

Detailed Forecast

Overnight
A 50 percent chance of showers and thunderstorms. Cloudy, with a low around 54. Light east wind.
Wednesday
Showers and thunderstorms likely, then showers and possibly a thunderstorm after 2pm. High near 70. Light and variable wind becoming south southwest 5 to 10 mph in the morning. Chance of precipitation is 90%.
Wednesday Night
Showers and thunderstorms before midnight, then showers and possibly a thunderstorm, mainly after midnight. Low around 57. South wind 6 to 8 mph. Chance of precipitation is 100%.
Thursday
Showers and possibly a thunderstorm before noon, then a chance of showers between noon and 3pm, then a chance of showers and thunderstorms after 3pm. High near 71. Southwest wind 7 to 11 mph. Chance of precipitation is 90%.
Thursday Night
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 59. South wind 5 to 8 mph.
Friday
A 30 percent chance of showers, mainly before noon. Partly sunny, with a high near 77. South wind 9 to 18 mph, with gusts as high as 26 mph.
Friday Night
A chance of showers before 9pm, then a chance of showers and thunderstorms between 9pm and midnight, then showers and possibly a thunderstorm after midnight. Low around 57. South wind 11 to 14 mph, with gusts as high as 23 mph. Chance of precipitation is 80%.
Saturday
Showers likely, mainly before noon. Mostly cloudy, with a high near 67. Southwest wind 7 to 13 mph becoming northwest in the afternoon. Winds could gust as high as 21 mph.
Saturday Night
A slight chance of showers before midnight. Partly cloudy, with a low around 41. Northwest wind around 6 mph becoming calm in the evening.
Sunday
Sunny, with a high near 65. Calm wind becoming southwest around 6 mph in the morning.
Sunday Night
Mostly clear, with a low around 48. South southwest wind 3 to 5 mph.
Monday
Sunny, with a high near 75. South southwest wind 5 to 10 mph.
Monday Night
A chance of showers and thunderstorms. Partly cloudy, with a low around 60. South southwest wind 8 to 10 mph, with gusts as high as 21 mph.
Tuesday
Showers likely and possibly a thunderstorm. Mostly cloudy, with a high near 76. South southwest wind 11 to 18 mph, with gusts as high as 28 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:
4:36 am CST Mar 4, 2026
Forecast Valid:
5am CST Mar 4, 2026-6pm CDT Mar 10, 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