National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Hazardous Weather Conditions

Current conditions at

Southern Illinois Airport (KMDH)

Lat: 37.78°NLon: 89.25°WElev: 400ft.

Mostly Cloudy and Breezy

76°F

24°C

Humidity 43%
Wind Speed S 22 G 35 mph
Barometer 29.98 in (1015.0 mb)
Dewpoint 52°F (11°C)
Visibility 10.00 mi
Heat Index78°F (26°C)
Last update 12 Apr 5:52 pm CDT
Extended Forecast for

Saint Johns IL

  • Tonight

    Tonight: A 50 percent chance of showers and thunderstorms, mainly between 10pm and 5am. Mostly cloudy, with a low around 65. South southwest wind 10 to 17 mph, with gusts as high as 26 mph.

    Low: 65 °F

    Chance
    T-storms

  • Monday

    Monday: A 30 percent chance of showers and thunderstorms before 7am. Mostly sunny, with a high near 82. South southwest wind 13 to 17 mph, with gusts as high as 25 mph.

    High: 82 °F

    Chance
    Showers then
    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 68. South southwest wind 14 to 16 mph, with gusts as high as 25 mph.

    Low: 68 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Partly sunny, with a high near 85. South southwest wind 13 to 17 mph, with gusts as high as 25 mph.

    High: 85 °F

    Partly Sunny

  • Tuesday Night

    Tuesday Night: A 20 percent chance of showers after 1am. Mostly cloudy, with a low around 68. South southwest wind 10 to 15 mph, with gusts as high as 24 mph.

    Low: 68 °F

    Mostly Cloudy
    then Slight
    Chance
    Showers

  • Wednesday

    Wednesday: A slight chance of showers, then a chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 83. South southwest wind 10 to 16 mph, with gusts as high as 24 mph. Chance of precipitation is 40%.

    High: 83 °F

    Chance
    Showers

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 64. South southwest wind 9 to 13 mph, with gusts as high as 21 mph. Chance of precipitation is 70%.

    Low: 64 °F

    Chance
    T-storms then
    Showers
    Likely

  • Thursday

    Thursday: A chance of showers and thunderstorms, mainly before 1pm. Partly sunny, with a high near 82. South southwest wind around 10 mph.

    High: 82 °F

    Chance
    Showers

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 63. South wind around 6 mph.

    Low: 63 °F

    Mostly Clear

Detailed Forecast

Tonight
A 50 percent chance of showers and thunderstorms, mainly between 10pm and 5am. Mostly cloudy, with a low around 65. South southwest wind 10 to 17 mph, with gusts as high as 26 mph.
Monday
A 30 percent chance of showers and thunderstorms before 7am. Mostly sunny, with a high near 82. South southwest wind 13 to 17 mph, with gusts as high as 25 mph.
Monday Night
Partly cloudy, with a low around 68. South southwest wind 14 to 16 mph, with gusts as high as 25 mph.
Tuesday
Partly sunny, with a high near 85. South southwest wind 13 to 17 mph, with gusts as high as 25 mph.
Tuesday Night
A 20 percent chance of showers after 1am. Mostly cloudy, with a low around 68. South southwest wind 10 to 15 mph, with gusts as high as 24 mph.
Wednesday
A slight chance of showers, then a chance of showers and thunderstorms after 1pm. Mostly cloudy, with a high near 83. South southwest wind 10 to 16 mph, with gusts as high as 24 mph. Chance of precipitation is 40%.
Wednesday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 64. South southwest wind 9 to 13 mph, with gusts as high as 21 mph. Chance of precipitation is 70%.
Thursday
A chance of showers and thunderstorms, mainly before 1pm. Partly sunny, with a high near 82. South southwest wind around 10 mph.
Thursday Night
Mostly clear, with a low around 63. South wind around 6 mph.
Friday
A slight chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 86. South wind 6 to 13 mph, with gusts as high as 20 mph.
Friday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 66. South wind around 10 mph, with gusts as high as 20 mph.
Saturday
A chance of showers and thunderstorms. Partly sunny, with a high near 80. Southwest wind 11 to 15 mph, with gusts as high as 21 mph.
Saturday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 46. West wind around 11 mph, with gusts as high as 20 mph.
Sunday
Mostly sunny, with a high near 64. Northwest wind around 10 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:
6:26 pm CDT Apr 12, 2026
Forecast Valid:
6pm CDT Apr 12, 2026-6pm CDT Apr 19, 2026
 
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