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

76°F

24°C

Humidity 52%
Wind Speed S 16 G 25 mph
Barometer 29.99 in (1015.5 mb)
Dewpoint 57°F (14°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 14 Nov 1:52 pm CST
Extended Forecast for

Saint Johns IL

  • This Afternoon

    This Afternoon: Sunny, with a high near 75. South southwest wind 11 to 13 mph, with gusts as high as 18 mph.

    High: 75 °F

    Sunny

  • Tonight

    Tonight: Increasing clouds, with a low around 59. South southwest wind 9 to 13 mph, with gusts as high as 20 mph.

    Low: 59 °F

    Increasing
    Clouds

  • Saturday

    Saturday: Mostly sunny, with a high near 76. Southwest wind 11 to 16 mph, with gusts as high as 23 mph.

    High: 76 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 45. West southwest wind 6 to 9 mph becoming north after midnight.

    Low: 45 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 61. North wind 5 to 8 mph.

    High: 61 °F

    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 39. Light and variable wind.

    Low: 39 °F

    Mostly Clear

  • Monday

    Monday: A 30 percent chance of showers after noon. Mostly sunny, with a high near 60. Light east wind becoming east southeast 5 to 9 mph in the morning.

    High: 60 °F

    Mostly Sunny
    then Chance
    Showers

  • Monday Night

    Monday Night: Showers. Mostly cloudy, with a low around 46. East wind 7 to 9 mph.

    Low: 46 °F

    Showers

  • Tuesday

    Tuesday: A chance of showers, mainly before noon. Partly sunny, with a high near 60. North wind 8 to 10 mph.

    High: 60 °F

    Chance
    Showers

Detailed Forecast

This Afternoon
Sunny, with a high near 75. South southwest wind 11 to 13 mph, with gusts as high as 18 mph.
Tonight
Increasing clouds, with a low around 59. South southwest wind 9 to 13 mph, with gusts as high as 20 mph.
Saturday
Mostly sunny, with a high near 76. Southwest wind 11 to 16 mph, with gusts as high as 23 mph.
Saturday Night
Mostly clear, with a low around 45. West southwest wind 6 to 9 mph becoming north after midnight.
Sunday
Sunny, with a high near 61. North wind 5 to 8 mph.
Sunday Night
Mostly clear, with a low around 39. Light and variable wind.
Monday
A 30 percent chance of showers after noon. Mostly sunny, with a high near 60. Light east wind becoming east southeast 5 to 9 mph in the morning.
Monday Night
Showers. Mostly cloudy, with a low around 46. East wind 7 to 9 mph.
Tuesday
A chance of showers, mainly before noon. Partly sunny, with a high near 60. North wind 8 to 10 mph.
Tuesday Night
A chance of showers, mainly after midnight. Mostly cloudy, with a low around 39. Northeast wind 5 to 7 mph.
Wednesday
A chance of showers. Partly sunny, with a high near 56. East wind around 7 mph.
Wednesday Night
Showers likely. Mostly cloudy, with a low around 43. East wind 6 to 8 mph.
Thursday
Showers likely. Mostly cloudy, with a high near 60. East wind 8 to 11 mph becoming south in the afternoon.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Saint Johns IL
 38.06°N 89.24°W
Last Update:
11:22 am CST Nov 14, 2025
Forecast Valid:
2pm CST Nov 14, 2025-6pm CST Nov 20, 2025
 
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Additional Resources

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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