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.

Fair

19°F

-7°C

Humidity 57%
Wind Speed N 6 mph
Barometer 30.40 in (1030.0 mb)
Dewpoint 6°F (-14°C)
Visibility 10.00 mi
Wind Chill11°F (-12°C)
Last update 27 Jan 11:52 pm CST
Extended Forecast for

Saint Johns IL

  • Overnight

    Overnight: Partly cloudy, with a low around -1. Wind chill values as low as -9. Light and variable wind.

    Low: -1 °F

    Partly Cloudy

  • Wednesday

    Wednesday: Sunny, with a high near 28. Wind chill values as low as -9. West wind 3 to 7 mph.

    High: 28 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly cloudy, with a low around 11. Light and variable wind.

    Low: 11 °F

    Mostly Cloudy

  • Thursday

    Thursday: Mostly cloudy, with a high near 26. Calm wind becoming northeast around 6 mph in the morning.

    High: 26 °F

    Mostly Cloudy

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 9. North northeast wind around 6 mph.

    Low: 9 °F

    Mostly Cloudy

  • Friday

    Friday: Partly sunny, with a high near 19. North wind 6 to 10 mph.

    High: 19 °F

    Partly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 2. North northwest wind 7 to 9 mph.

    Low: 2 °F

    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 16. Northwest wind 6 to 10 mph.

    High: 16 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Partly cloudy, with a low around 1. Northwest wind 3 to 5 mph.

    Low: 1 °F

    Partly Cloudy

Detailed Forecast

Overnight
Partly cloudy, with a low around -1. Wind chill values as low as -9. Light and variable wind.
Wednesday
Sunny, with a high near 28. Wind chill values as low as -9. West wind 3 to 7 mph.
Wednesday Night
Mostly cloudy, with a low around 11. Light and variable wind.
Thursday
Mostly cloudy, with a high near 26. Calm wind becoming northeast around 6 mph in the morning.
Thursday Night
Mostly cloudy, with a low around 9. North northeast wind around 6 mph.
Friday
Partly sunny, with a high near 19. North wind 6 to 10 mph.
Friday Night
Partly cloudy, with a low around 2. North northwest wind 7 to 9 mph.
Saturday
Mostly sunny, with a high near 16. Northwest wind 6 to 10 mph.
Saturday Night
Partly cloudy, with a low around 1. Northwest wind 3 to 5 mph.
Sunday
Mostly sunny, with a high near 25. West wind 5 to 7 mph becoming south southwest in the afternoon.
Sunday Night
Mostly cloudy, with a low around 12. South southwest wind around 6 mph.
Monday
Partly sunny, with a high near 34. West southwest wind 5 to 7 mph.
Monday Night
Mostly cloudy, with a low around 18. Southwest wind 3 to 5 mph.
Tuesday
Mostly cloudy, with a high near 35. South southeast wind 5 to 7 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:
12:36 am CST Jan 28, 2026
Forecast Valid:
12am CST Jan 28, 2026-6pm CST Feb 3, 2026
 
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Additional Resources

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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