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

82°F

28°C

Humidity 26%
Wind Speed S 10 G 18 mph
Barometer 29.99 in
Dewpoint 45°F (7°C)
Visibility 10.00 mi
Heat Index80°F (27°C)
Last update 29 Sep 1:52 pm CDT
Extended Forecast for

Alto Pass IL

  • This Afternoon

    This Afternoon: Sunny, with a high near 82. South wind 3 to 5 mph.

    High: 82 °F

    Sunny

  • Tonight

    Tonight: Mostly cloudy, with a low around 59. Calm wind becoming south southeast around 5 mph after midnight.

    Low: 59 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Mostly cloudy during the morning, then sunny during the afternoon, with a high near 88. South southwest wind 6 to 8 mph.

    High: 88 °F

    Partly Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 70. South southeast wind 5 to 7 mph.

    Low: 70 °F

    Mostly Cloudy

  • Thursday

    Thursday: Partly sunny, with a high near 88. South southwest wind 7 to 11 mph, with gusts as high as 20 mph.

    High: 88 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: A 50 percent chance of showers, mainly after 1am. Mostly cloudy, with a low around 68. South wind around 5 mph.

    Low: 68 °F

    Slight Chance
    Showers then
    Chance
    Showers

  • Friday

    Friday: Showers and possibly a thunderstorm. High near 73. South southwest wind 5 to 8 mph becoming north in the afternoon. Chance of precipitation is 90%.

    High: 73 °F

    Showers

  • Friday Night

    Friday Night: A chance of showers. Mostly cloudy, with a low around 59. North northeast wind around 8 mph.

    Low: 59 °F

    Chance
    Showers

  • Saturday

    Saturday: A chance of showers. Mostly cloudy, with a high near 68. Northeast wind around 8 mph.

    High: 68 °F

    Chance
    Showers

Detailed Forecast

This Afternoon
Sunny, with a high near 82. South wind 3 to 5 mph.
Tonight
Mostly cloudy, with a low around 59. Calm wind becoming south southeast around 5 mph after midnight.
Wednesday
Mostly cloudy during the morning, then sunny during the afternoon, with a high near 88. South southwest wind 6 to 8 mph.
Wednesday Night
Mostly cloudy, with a low around 70. South southeast wind 5 to 7 mph.
Thursday
Partly sunny, with a high near 88. South southwest wind 7 to 11 mph, with gusts as high as 20 mph.
Thursday Night
A 50 percent chance of showers, mainly after 1am. Mostly cloudy, with a low around 68. South wind around 5 mph.
Friday
Showers and possibly a thunderstorm. High near 73. South southwest wind 5 to 8 mph becoming north in the afternoon. Chance of precipitation is 90%.
Friday Night
A chance of showers. Mostly cloudy, with a low around 59. North northeast wind around 8 mph.
Saturday
A chance of showers. Mostly cloudy, with a high near 68. Northeast wind around 8 mph.
Saturday Night
A chance of showers, mainly before 1am. Mostly cloudy, with a low around 56. Northeast wind around 5 mph becoming calm.
Sunday
Mostly sunny, with a high near 69. North wind 5 to 8 mph.
Sunday Night
Mostly clear, with a low around 52. North wind around 6 mph.
Monday
Sunny, with a high near 68. North northeast wind 6 to 9 mph.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Alto Pass IL
 37.57°N 89.32°W
Last Update:
1:27 pm CDT Sep 29, 2026
Forecast Valid:
1pm CDT Sep 29, 2026-6pm CDT Oct 5, 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