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

86°F

30°C

Humidity 46%
Wind Speed NE 3 mph
Barometer 30.03 in
Dewpoint 63°F (17°C)
Visibility 10.00 mi
Heat Index87°F (31°C)
Last update 4 Aug 1:50 pm CDT
Extended Forecast for

Grand Tower IL

  • This Afternoon

    This Afternoon: Sunny, with a high near 88. Calm wind.

    High: 88 °F

    Sunny

  • Tonight

    Tonight: Patchy fog after 5am. Otherwise, mostly clear, with a low around 65. Light east southeast wind.

    Low: 65 °F

    Mostly Clear
    then Patchy
    Fog

  • Wednesday

    Wednesday: Patchy fog before 8am. Otherwise, sunny, with a high near 90. Calm wind becoming south southwest around 5 mph in the morning.

    High: 90 °F

    Patchy Fog
    then Sunny

  • Wednesday Night

    Wednesday Night: A 10 percent chance of showers after 5am. Increasing clouds, with a low around 70. Light south southeast wind.

    Low: 70 °F

    Mostly Clear
    then Slight
    Chance
    Showers

  • Thursday

    Thursday: A 50 percent chance of showers and thunderstorms before 1pm. Partly sunny, with a high near 87. Light south wind.

    High: 87 °F

    Chance
    T-storms

  • Thursday Night

    Thursday Night: A slight chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 70. Calm wind. Chance of precipitation is 60%.

    Low: 70 °F

    Slight Chance
    T-storms then
    Showers
    Likely

  • Friday

    Friday: Showers likely and possibly a thunderstorm before 1pm, then a slight chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 87. Calm wind becoming south southwest around 5 mph in the afternoon. Chance of precipitation is 60%.

    High: 87 °F

    Showers
    Likely

  • Friday Night

    Friday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 70. Light south southwest wind.

    Low: 70 °F

    Chance
    T-storms

  • Saturday

    Saturday: A slight chance of showers and thunderstorms. Mostly sunny, with a high near 89. Light south southwest wind.

    High: 89 °F

    Slight Chance
    T-storms

Detailed Forecast

This Afternoon
Sunny, with a high near 88. Calm wind.
Tonight
Patchy fog after 5am. Otherwise, mostly clear, with a low around 65. Light east southeast wind.
Wednesday
Patchy fog before 8am. Otherwise, sunny, with a high near 90. Calm wind becoming south southwest around 5 mph in the morning.
Wednesday Night
A 10 percent chance of showers after 5am. Increasing clouds, with a low around 70. Light south southeast wind.
Thursday
A 50 percent chance of showers and thunderstorms before 1pm. Partly sunny, with a high near 87. Light south wind.
Thursday Night
A slight chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 70. Calm wind. Chance of precipitation is 60%.
Friday
Showers likely and possibly a thunderstorm before 1pm, then a slight chance of showers and thunderstorms after 1pm. Partly sunny, with a high near 87. Calm wind becoming south southwest around 5 mph in the afternoon. Chance of precipitation is 60%.
Friday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 70. Light south southwest wind.
Saturday
A slight chance of showers and thunderstorms. Mostly sunny, with a high near 89. Light south southwest wind.
Saturday Night
Mostly clear, with a low around 71. Light south wind.
Sunday
Sunny, with a high near 91. Light south wind becoming south southwest 5 to 9 mph in the morning.
Sunday Night
Mostly clear, with a low around 74. South wind around 7 mph.
Monday
Sunny, with a high near 94. South southwest wind 7 to 11 mph.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Grand Tower IL
 37.64°N 89.52°W
Last Update:
1:54 pm CDT Aug 4, 2026
Forecast Valid:
2pm CDT Aug 4, 2026-6pm CDT Aug 10, 2026
 
Forecast Discussion
 
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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