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

57°F

14°C

Humidity 69%
Wind Speed S 9 mph
Barometer 30.08 in (1018.5 mb)
Dewpoint 47°F (8°C)
Visibility 10.00 mi
Last update 5 Nov 7:52 am CST
Extended Forecast for

Saint Johns IL

  • Today

    Today: Sunny, with a high near 71. Southwest wind 9 to 14 mph becoming north northwest in the afternoon. Winds could gust as high as 21 mph.

    High: 71 °F

    Sunny

  • Tonight

    Tonight: Clear, with a low around 39. North northwest wind 5 to 8 mph becoming light and variable.

    Low: 39 °F

    Clear

  • Thursday

    Thursday: Sunny, with a high near 65. Southeast wind 5 to 10 mph.

    High: 65 °F

    Sunny

  • Thursday Night

    Thursday Night: A 20 percent chance of showers after midnight. Increasing clouds, with a low around 52. Southeast wind 7 to 14 mph becoming south southwest after midnight. Winds could gust as high as 20 mph.

    Low: 52 °F

    Partly Cloudy
    then Slight
    Chance
    Showers

  • Friday

    Friday: Showers likely and possibly a thunderstorm before 9am, then showers likely between 9am and noon, then a chance of showers and thunderstorms after noon. Mostly sunny, with a high near 72. West wind 8 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 60%.

    High: 72 °F

    Showers
    Likely then
    Chance
    Showers

  • Friday Night

    Friday Night: Mostly clear, with a low around 43. West wind around 6 mph becoming calm in the evening.

    Low: 43 °F

    Mostly Clear

  • Saturday

    Saturday: Mostly sunny, with a high near 67. Light and variable wind becoming southwest 5 to 10 mph in the morning.

    High: 67 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: A chance of showers, mainly before midnight. Partly cloudy, with a low around 38. West southwest wind 10 to 13 mph becoming northwest after midnight. Winds could gust as high as 20 mph.

    Low: 38 °F

    Chance
    Showers

  • Sunday

    Sunday: Mostly sunny, with a high near 47. Northwest wind 14 to 18 mph, with gusts as high as 25 mph.

    High: 47 °F

    Mostly Sunny

Detailed Forecast

Today
Sunny, with a high near 71. Southwest wind 9 to 14 mph becoming north northwest in the afternoon. Winds could gust as high as 21 mph.
Tonight
Clear, with a low around 39. North northwest wind 5 to 8 mph becoming light and variable.
Thursday
Sunny, with a high near 65. Southeast wind 5 to 10 mph.
Thursday Night
A 20 percent chance of showers after midnight. Increasing clouds, with a low around 52. Southeast wind 7 to 14 mph becoming south southwest after midnight. Winds could gust as high as 20 mph.
Friday
Showers likely and possibly a thunderstorm before 9am, then showers likely between 9am and noon, then a chance of showers and thunderstorms after noon. Mostly sunny, with a high near 72. West wind 8 to 15 mph, with gusts as high as 21 mph. Chance of precipitation is 60%.
Friday Night
Mostly clear, with a low around 43. West wind around 6 mph becoming calm in the evening.
Saturday
Mostly sunny, with a high near 67. Light and variable wind becoming southwest 5 to 10 mph in the morning.
Saturday Night
A chance of showers, mainly before midnight. Partly cloudy, with a low around 38. West southwest wind 10 to 13 mph becoming northwest after midnight. Winds could gust as high as 20 mph.
Sunday
Mostly sunny, with a high near 47. Northwest wind 14 to 18 mph, with gusts as high as 25 mph.
Sunday Night
Mostly clear, with a low around 24. Northwest wind 7 to 13 mph.
Monday
Sunny, with a high near 44. Northwest wind 8 to 13 mph.
Monday Night
Mostly clear, with a low around 26. West southwest wind 3 to 6 mph.
Veterans Day
Sunny, with a high near 53. South southwest wind 7 to 15 mph, with gusts as high as 21 mph.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Saint Johns IL
 38.03°N 89.21°W
Last Update:
7:52 am CST Nov 5, 2025
Forecast Valid:
8am CST Nov 5, 2025-6pm CST Nov 11, 2025
 
Forecast Discussion
 
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Additional Resources

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation