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.

Partly Cloudy

63°F

17°C

Humidity 78%
Wind Speed SW 9 mph
Barometer 29.87 in (1011.0 mb)
Dewpoint 56°F (13°C)
Visibility 10.00 mi
Last update 15 Nov 3:52 am CST
Extended Forecast for

Saint Johns IL

  • Today

    Today: Mostly sunny, with a high near 76. South southwest wind 10 to 17 mph, with gusts as high as 23 mph.

    High: 76 °F

    Mostly Sunny

  • Tonight

    Tonight: Mostly clear, with a low around 45. West wind around 8 mph becoming north after midnight.

    Low: 45 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 60. North wind 3 to 8 mph.

    High: 60 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 36. Calm wind.

    Low: 36 °F

    Mostly Clear

  • Monday

    Monday: A 20 percent chance of showers after noon. Mostly sunny, with a high near 60. Calm wind becoming southeast 5 to 9 mph in the morning.

    High: 60 °F

    Sunny then
    Slight Chance
    Showers

  • Monday Night

    Monday Night: Showers and possibly a thunderstorm. Low around 47. Southeast wind 7 to 10 mph. Chance of precipitation is 80%.

    Low: 47 °F

    Showers

  • Tuesday

    Tuesday: A 30 percent chance of showers before noon. Partly sunny, with a high near 71. South southeast wind 9 to 11 mph becoming north in the afternoon. Winds could gust as high as 18 mph.

    High: 71 °F

    Chance
    Showers then
    Partly Sunny

  • Tuesday Night

    Tuesday Night: A slight chance of showers. Mostly cloudy, with a low around 46. North wind 5 to 8 mph.

    Low: 46 °F

    Slight Chance
    Showers

  • Wednesday

    Wednesday: A chance of showers, mainly after noon. Partly sunny, with a high near 63. Northeast wind 5 to 7 mph becoming southeast in the morning.

    High: 63 °F

    Chance
    Showers

Detailed Forecast

Today
Mostly sunny, with a high near 76. South southwest wind 10 to 17 mph, with gusts as high as 23 mph.
Tonight
Mostly clear, with a low around 45. West wind around 8 mph becoming north after midnight.
Sunday
Sunny, with a high near 60. North wind 3 to 8 mph.
Sunday Night
Mostly clear, with a low around 36. Calm wind.
Monday
A 20 percent chance of showers after noon. Mostly sunny, with a high near 60. Calm wind becoming southeast 5 to 9 mph in the morning.
Monday Night
Showers and possibly a thunderstorm. Low around 47. Southeast wind 7 to 10 mph. Chance of precipitation is 80%.
Tuesday
A 30 percent chance of showers before noon. Partly sunny, with a high near 71. South southeast wind 9 to 11 mph becoming north in the afternoon. Winds could gust as high as 18 mph.
Tuesday Night
A slight chance of showers. Mostly cloudy, with a low around 46. North wind 5 to 8 mph.
Wednesday
A chance of showers, mainly after noon. Partly sunny, with a high near 63. Northeast wind 5 to 7 mph becoming southeast in the morning.
Wednesday Night
Showers likely, mainly after midnight. Mostly cloudy, with a low around 51. Southeast wind 5 to 7 mph.
Thursday
Showers and possibly a thunderstorm. Mostly cloudy, with a high near 66. South southeast wind 7 to 11 mph.
Thursday Night
Showers likely. Mostly cloudy, with a low around 53. South southeast wind 8 to 10 mph.
Friday
A chance of showers. Mostly cloudy, with a high near 66. South southwest wind 10 to 13 mph, with gusts as high as 20 mph.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Saint Johns IL
 38.03°N 89.24°W
Last Update:
3:16 am CST Nov 15, 2025
Forecast Valid:
4am CST Nov 15, 2025-6pm CST Nov 21, 2025
 
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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