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.

Mostly Cloudy

82°F

28°C

Humidity 70%
Wind Speed Calm
Barometer 29.99 in
Dewpoint 72°F (22°C)
Visibility 10.00 mi
Heat Index86°F (30°C)
Last update 20 Aug 12:49 pm CDT
Extended Forecast for

Jacob IL

  • This Afternoon

    This Afternoon: A slight chance of showers and thunderstorms between 2pm and 3pm. Mostly sunny, with a high near 84. North wind around 7 mph. Chance of precipitation is 20%.

    High: 84 °F

    Slight Chance
    T-storms

  • Tonight

    Tonight: Patchy fog after 1am. Otherwise, mostly clear, with a low around 66. Light north wind.

    Low: 66 °F

    Mostly Clear
    then Patchy
    Fog

  • Friday

    Friday: Areas of fog before 9am. Otherwise, sunny, with a high near 86. Calm wind.

    High: 86 °F

    Areas Fog
    then Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 67. Calm wind.

    Low: 67 °F

    Mostly Clear

  • Saturday

    Saturday: A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 86. Calm wind becoming north northwest 5 to 7 mph in the afternoon.

    High: 86 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 64. Light north wind.

    Low: 64 °F

    Mostly Clear

  • Sunday

    Sunday: Mostly sunny, with a high near 83. Calm wind becoming north around 6 mph in the afternoon.

    High: 83 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 62. Calm wind.

    Low: 62 °F

    Partly Cloudy

  • Monday

    Monday: A slight chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 82. Light east southeast wind.

    High: 82 °F

    Mostly Sunny
    then Slight
    Chance
    T-storms

Detailed Forecast

This Afternoon
A slight chance of showers and thunderstorms between 2pm and 3pm. Mostly sunny, with a high near 84. North wind around 7 mph. Chance of precipitation is 20%.
Tonight
Patchy fog after 1am. Otherwise, mostly clear, with a low around 66. Light north wind.
Friday
Areas of fog before 9am. Otherwise, sunny, with a high near 86. Calm wind.
Friday Night
Mostly clear, with a low around 67. Calm wind.
Saturday
A 20 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 86. Calm wind becoming north northwest 5 to 7 mph in the afternoon.
Saturday Night
Mostly clear, with a low around 64. Light north wind.
Sunday
Mostly sunny, with a high near 83. Calm wind becoming north around 6 mph in the afternoon.
Sunday Night
Partly cloudy, with a low around 62. Calm wind.
Monday
A slight chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 82. Light east southeast wind.
Monday Night
A slight chance of showers, with thunderstorms also possible after 1am. Partly cloudy, with a low around 64. Light east southeast wind.
Tuesday
A slight chance of showers. Mostly sunny, with a high near 86. Calm wind becoming south southeast around 5 mph in the afternoon.
Tuesday Night
Partly cloudy, with a low around 66. Calm wind.
Wednesday
A slight chance of showers and thunderstorms. Mostly sunny, with a high near 87. Calm wind becoming northwest around 5 mph in the afternoon.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Jacob IL
 37.75°N 89.54°W
Last Update:
11:26 am CDT Aug 20, 2026
Forecast Valid:
1pm CDT Aug 20, 2026-6pm CDT Aug 26, 2026
 
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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