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

42°F

6°C

Humidity 68%
Wind Speed Calm
Barometer 30.10 in (1019.4 mb)
Dewpoint 32°F (0°C)
Visibility 10.00 mi
Last update 14 Feb 7:52 am CST
Extended Forecast for

Saint Johns IL

  • Today

    Today: Rain, mainly after 11am. High near 52. Calm wind becoming east 5 to 9 mph in the afternoon. Chance of precipitation is 100%.

    High: 52 °F

    Rain Likely
    then Rain

  • Tonight

    Tonight: Rain. Steady temperature around 48. East wind 7 to 11 mph, with gusts as high as 20 mph. Chance of precipitation is 100%.

    Low: 48 °F

    Rain

  • Sunday

    Sunday: A 50 percent chance of rain, mainly before 9am. Cloudy, then gradually becoming mostly sunny, with a high near 57. North northeast wind 7 to 10 mph.

    High: 57 °F

    Chance Rain
    then Mostly
    Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 37. North wind around 5 mph becoming calm in the evening.

    Low: 37 °F

    Mostly Clear

  • Washington's Birthday

    Washington's Birthday: Mostly sunny, with a high near 61. Calm wind becoming south 5 to 8 mph in the morning.

    High: 61 °F

    Mostly Sunny

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 45. South wind around 6 mph.

    Low: 45 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: Mostly cloudy, with a high near 64. South wind 7 to 17 mph, with gusts as high as 26 mph.

    High: 64 °F

    Mostly Cloudy

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 56. Breezy, with a south southwest wind 16 to 20 mph, with gusts as high as 30 mph.

    Low: 56 °F

    Mostly Cloudy
    and Breezy

  • Wednesday

    Wednesday: Partly sunny, with a high near 71. West southwest wind 9 to 15 mph, with gusts as high as 25 mph.

    High: 71 °F

    Partly Sunny

Detailed Forecast

Today
Rain, mainly after 11am. High near 52. Calm wind becoming east 5 to 9 mph in the afternoon. Chance of precipitation is 100%.
Tonight
Rain. Steady temperature around 48. East wind 7 to 11 mph, with gusts as high as 20 mph. Chance of precipitation is 100%.
Sunday
A 50 percent chance of rain, mainly before 9am. Cloudy, then gradually becoming mostly sunny, with a high near 57. North northeast wind 7 to 10 mph.
Sunday Night
Mostly clear, with a low around 37. North wind around 5 mph becoming calm in the evening.
Washington's Birthday
Mostly sunny, with a high near 61. Calm wind becoming south 5 to 8 mph in the morning.
Monday Night
Mostly cloudy, with a low around 45. South wind around 6 mph.
Tuesday
Mostly cloudy, with a high near 64. South wind 7 to 17 mph, with gusts as high as 26 mph.
Tuesday Night
Mostly cloudy, with a low around 56. Breezy, with a south southwest wind 16 to 20 mph, with gusts as high as 30 mph.
Wednesday
Partly sunny, with a high near 71. West southwest wind 9 to 15 mph, with gusts as high as 25 mph.
Wednesday Night
Partly cloudy, with a low around 49. Southwest wind around 8 mph.
Thursday
A chance of rain. Mostly sunny, with a high near 70. South wind 7 to 13 mph, with gusts as high as 22 mph.
Thursday Night
A slight chance of rain and thunderstorms. Mostly cloudy, with a low around 44. West southwest wind 9 to 11 mph, with gusts as high as 20 mph.
Friday
Partly sunny, with a high near 58. West wind 8 to 11 mph, with gusts as high as 18 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:
7:06 am CST Feb 14, 2026
Forecast Valid:
8am CST Feb 14, 2026-6pm CST Feb 20, 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