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.

Fog/Mist

57°F

14°C

Humidity 100%
Wind Speed N 12 mph
Barometer 29.93 in (1013.4 mb)
Dewpoint 57°F (14°C)
Visibility 4.00 mi
Last update 21 Nov 11:52 pm CST
Extended Forecast for

Saint Johns IL

  • Overnight

    Overnight: Areas of fog. Otherwise, mostly cloudy, with a low around 47. North wind 7 to 9 mph.

    Low: 47 °F

    Areas Fog

  • Saturday

    Saturday: Patchy fog before 9am. Otherwise, cloudy through mid morning, then gradual clearing, with a high near 59. North wind 5 to 7 mph.

    High: 59 °F

    Patchy Fog
    then Mostly
    Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 40. Light west wind.

    Low: 40 °F

    Mostly Clear

  • Sunday

    Sunday: Sunny, with a high near 62. Light and variable wind.

    High: 62 °F

    Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 41. Light southeast wind.

    Low: 41 °F

    Partly Cloudy

  • Monday

    Monday: Showers likely, mainly after noon. Cloudy, with a high near 59. Light southeast wind becoming south southeast 5 to 10 mph in the morning. Chance of precipitation is 70%.

    High: 59 °F

    Slight Chance
    Showers then
    Showers
    Likely

  • Monday Night

    Monday Night: Showers. Low around 51. South southeast wind 7 to 9 mph becoming southwest after midnight. Chance of precipitation is 90%.

    Low: 51 °F

    Showers then
    Showers
    Likely

  • Tuesday

    Tuesday: A chance of showers, mainly before noon. Partly sunny, with a high near 64. Southwest wind 7 to 10 mph becoming west northwest in the afternoon.

    High: 64 °F

    Chance
    Showers

  • Tuesday Night

    Tuesday Night: Partly cloudy, with a low around 36. Northwest wind around 7 mph.

    Low: 36 °F

    Partly Cloudy

Detailed Forecast

Overnight
Areas of fog. Otherwise, mostly cloudy, with a low around 47. North wind 7 to 9 mph.
Saturday
Patchy fog before 9am. Otherwise, cloudy through mid morning, then gradual clearing, with a high near 59. North wind 5 to 7 mph.
Saturday Night
Mostly clear, with a low around 40. Light west wind.
Sunday
Sunny, with a high near 62. Light and variable wind.
Sunday Night
Partly cloudy, with a low around 41. Light southeast wind.
Monday
Showers likely, mainly after noon. Cloudy, with a high near 59. Light southeast wind becoming south southeast 5 to 10 mph in the morning. Chance of precipitation is 70%.
Monday Night
Showers. Low around 51. South southeast wind 7 to 9 mph becoming southwest after midnight. Chance of precipitation is 90%.
Tuesday
A chance of showers, mainly before noon. Partly sunny, with a high near 64. Southwest wind 7 to 10 mph becoming west northwest in the afternoon.
Tuesday Night
Partly cloudy, with a low around 36. Northwest wind around 7 mph.
Wednesday
Mostly sunny, with a high near 50. West northwest wind 7 to 11 mph.
Wednesday Night
Mostly clear, with a low around 29. West wind around 6 mph.
Thanksgiving Day
Mostly sunny, with a high near 48. West wind 5 to 9 mph.
Thursday Night
Mostly cloudy, with a low around 30. Light and variable wind.
Friday
A slight chance of rain and snow showers. Mostly sunny, with a high near 47. North northwest wind 3 to 8 mph.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Saint Johns IL
 38.03°N 89.24°W
Last Update:
9:56 pm CST Nov 21, 2025
Forecast Valid:
12am CST Nov 22, 2025-6pm CST Nov 28, 2025
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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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