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

50°F

10°C

Humidity 41%
Wind Speed Vrbl 6 mph
Barometer 30.30 in (1026.1 mb)
Dewpoint 27°F (-3°C)
Visibility 10.00 mi
Wind Chill48°F (9°C)
Last update 12 Feb 11:52 am CST
Extended Forecast for

Saint Johns IL

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 52. Southeast wind around 6 mph.

    High: 52 °F

    Mostly Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 30. East southeast wind 3 to 5 mph.

    Low: 30 °F

    Partly Cloudy

  • Friday

    Friday: Sunny, with a high near 57. Calm wind becoming south southeast 5 to 7 mph.

    High: 57 °F

    Sunny

  • Friday Night

    Friday Night: Increasing clouds, with a low around 37. Calm wind.

    Low: 37 °F

    Increasing
    Clouds

  • Saturday

    Saturday: Rain likely, mainly after noon. Cloudy, with a high near 52. Calm wind becoming southeast 5 to 7 mph in the morning. Chance of precipitation is 60%.

    High: 52 °F

    Chance Rain
    then Rain
    Likely

  • Saturday Night

    Saturday Night: Rain. Low around 45. East wind 6 to 9 mph. Chance of precipitation is 90%.

    Low: 45 °F

    Rain

  • Sunday

    Sunday: A 40 percent chance of rain, mainly before noon. Partly sunny, with a high near 56. North wind 7 to 10 mph.

    High: 56 °F

    Chance Rain

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 35. North wind around 6 mph becoming calm in the evening.

    Low: 35 °F

    Mostly Clear

  • Washington's Birthday

    Washington's Birthday: Mostly sunny, with a high near 60. Calm wind becoming south 5 to 7 mph in the morning.

    High: 60 °F

    Mostly Sunny

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 52. Southeast wind around 6 mph.
Tonight
Partly cloudy, with a low around 30. East southeast wind 3 to 5 mph.
Friday
Sunny, with a high near 57. Calm wind becoming south southeast 5 to 7 mph.
Friday Night
Increasing clouds, with a low around 37. Calm wind.
Saturday
Rain likely, mainly after noon. Cloudy, with a high near 52. Calm wind becoming southeast 5 to 7 mph in the morning. Chance of precipitation is 60%.
Saturday Night
Rain. Low around 45. East wind 6 to 9 mph. Chance of precipitation is 90%.
Sunday
A 40 percent chance of rain, mainly before noon. Partly sunny, with a high near 56. North wind 7 to 10 mph.
Sunday Night
Mostly clear, with a low around 35. North wind around 6 mph becoming calm in the evening.
Washington's Birthday
Mostly sunny, with a high near 60. Calm wind becoming south 5 to 7 mph in the morning.
Monday Night
Mostly cloudy, with a low around 44. South wind around 6 mph.
Tuesday
Mostly cloudy, with a high near 64. South wind 7 to 15 mph, with gusts as high as 23 mph.
Tuesday Night
Mostly cloudy, with a low around 54. South southwest wind 14 to 16 mph, with gusts as high as 25 mph.
Wednesday
A slight chance of rain. Mostly cloudy, with a high near 66. West southwest wind 13 to 15 mph, with gusts as high as 24 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:
10:41 am CST Feb 12, 2026
Forecast Valid:
12pm CST Feb 12, 2026-6pm CST Feb 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