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

84°F

29°C

Humidity 40%
Wind Speed NW 12 G 18 mph
Barometer 30.06 in
Dewpoint 57°F (14°C)
Visibility 10.00 mi
Heat Index83°F (28°C)
Last update 23 Aug 1:52 pm CDT
Extended Forecast for

3 Miles NNE Saint Johns IL

  • This Afternoon

    This Afternoon: Mostly sunny, with a high near 83. Northwest wind around 7 mph.

    High: 83 °F

    Mostly Sunny

  • Tonight

    Tonight: Patchy fog after 1am. Otherwise, partly cloudy, with a low around 58. Light north wind.

    Low: 58 °F

    Partly Cloudy
    then Patchy
    Fog

  • Monday

    Monday: Patchy fog before 8am. Otherwise, mostly sunny, with a high near 85. Calm wind.

    High: 85 °F

    Patchy Fog
    then Mostly
    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 62. Calm wind.

    Low: 62 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 88. Light east wind.

    High: 88 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 66. Calm wind.

    Low: 66 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Mostly sunny, with a high near 90. Calm wind becoming southwest around 5 mph in the afternoon.

    High: 90 °F

    Mostly Sunny

  • Wednesday Night

    Wednesday Night: A slight chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 68. Calm wind.

    Low: 68 °F

    Slight Chance
    T-storms

  • Thursday

    Thursday: Sunny, with a high near 89. Calm wind becoming north northwest 5 to 8 mph in the afternoon.

    High: 89 °F

    Sunny

Detailed Forecast

This Afternoon
Mostly sunny, with a high near 83. Northwest wind around 7 mph.
Tonight
Patchy fog after 1am. Otherwise, partly cloudy, with a low around 58. Light north wind.
Monday
Patchy fog before 8am. Otherwise, mostly sunny, with a high near 85. Calm wind.
Monday Night
Mostly clear, with a low around 62. Calm wind.
Tuesday
Sunny, with a high near 88. Light east wind.
Tuesday Night
Partly cloudy, with a low around 66. Calm wind.
Wednesday
Mostly sunny, with a high near 90. Calm wind becoming southwest around 5 mph in the afternoon.
Wednesday Night
A slight chance of showers and thunderstorms before 1am. Partly cloudy, with a low around 68. Calm wind.
Thursday
Sunny, with a high near 89. Calm wind becoming north northwest 5 to 8 mph in the afternoon.
Thursday Night
Mostly clear, with a low around 65. Light north wind.
Friday
Sunny, with a high near 89. Light north wind.
Friday Night
Mostly clear, with a low around 65. Calm wind.
Saturday
Mostly sunny, with a high near 90. Calm wind becoming south around 5 mph in the afternoon.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
3 Miles NNE Saint Johns IL
 38.08°N 89.21°W
Last Update:
1:26 pm CDT Aug 23, 2026
Forecast Valid:
2pm CDT Aug 23, 2026-6pm CDT Aug 29, 2026
 
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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