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

66°F

19°C

Humidity 39%
Wind Speed NW 14 mph
Barometer 30.26 in (1024.7 mb)
Dewpoint 40°F (4°C)
Visibility 10.00 mi
Last update 6 Apr 2:52 pm CDT
Extended Forecast for

Saint Johns IL

  • This Afternoon

    This Afternoon: Sunny, with a high near 65. Northwest wind around 9 mph, with gusts as high as 18 mph.

    High: 65 °F

    Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 39. North northeast wind around 7 mph.

    Low: 39 °F

    Mostly Clear

  • Tuesday

    Tuesday: Mostly sunny, with a high near 57. East northeast wind 9 to 13 mph, with gusts as high as 20 mph.

    High: 57 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 38. East southeast wind around 7 mph.

    Low: 38 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 73. South wind 6 to 11 mph, with gusts as high as 18 mph.

    High: 73 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 53. South wind around 9 mph.

    Low: 53 °F

    Partly Cloudy

  • Thursday

    Thursday: Sunny, with a high near 74. South wind 9 to 11 mph, with gusts as high as 18 mph.

    High: 74 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 54. South wind around 7 mph.

    Low: 54 °F

    Mostly Clear

  • Friday

    Friday: A chance of showers, with thunderstorms also possible after 1pm. Mostly sunny, with a high near 76. South southwest wind 6 to 9 mph.

    High: 76 °F

    Chance
    Showers

Detailed Forecast

This Afternoon
Sunny, with a high near 65. Northwest wind around 9 mph, with gusts as high as 18 mph.
Tonight
Mostly clear, with a low around 39. North northeast wind around 7 mph.
Tuesday
Mostly sunny, with a high near 57. East northeast wind 9 to 13 mph, with gusts as high as 20 mph.
Tuesday Night
Partly cloudy, with a low around 38. East southeast wind around 7 mph.
Wednesday
Mostly sunny, with a high near 73. South wind 6 to 11 mph, with gusts as high as 18 mph.
Wednesday Night
Partly cloudy, with a low around 53. South wind around 9 mph.
Thursday
Sunny, with a high near 74. South wind 9 to 11 mph, with gusts as high as 18 mph.
Thursday Night
Mostly clear, with a low around 54. South wind around 7 mph.
Friday
A chance of showers, with thunderstorms also possible after 1pm. Mostly sunny, with a high near 76. South southwest wind 6 to 9 mph.
Friday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 57. West southwest wind around 5 mph becoming light and variable after midnight.
Saturday
A slight chance of showers and thunderstorms. Mostly sunny, with a high near 78. East wind 5 to 7 mph becoming south southeast in the afternoon.
Saturday Night
Partly cloudy, with a low around 60. Southeast wind around 7 mph.
Sunday
Partly sunny, with a high near 83. South wind 8 to 15 mph, with gusts as high as 23 mph.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Saint Johns IL
 38.03°N 89.24°W
Last Update:
2:52 pm CDT Apr 6, 2026
Forecast Valid:
2pm CDT Apr 6, 2026-6pm CDT Apr 12, 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