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.

Overcast

66°F

19°C

Humidity 90%
Wind Speed S 17 G 24 mph
Barometer 30.00 in (1015.6 mb)
Dewpoint 63°F (17°C)
Visibility 10.00 mi
Last update 5 Mar 11:52 am CST
Extended Forecast for

Saint Johns IL

  • This Afternoon

    This Afternoon: A 40 percent chance of showers and thunderstorms, mainly between 1pm and 4pm. Mostly cloudy, with a steady temperature around 67. Southwest wind 5 to 10 mph becoming light west.

    High: 67 °F

    Chance
    Showers

  • Tonight

    Tonight: A chance of showers and thunderstorms. Mostly cloudy, with a low around 59. Calm wind becoming south southeast around 6 mph after midnight. Chance of precipitation is 40%.

    Low: 59 °F

    Chance
    T-storms

  • Friday

    Friday: A 20 percent chance of showers before 8am. Mostly sunny, with a high near 76. South wind 7 to 17 mph, with gusts as high as 25 mph.

    High: 76 °F

    Slight Chance
    Showers then
    Partly Sunny

  • Friday Night

    Friday Night: Showers likely and possibly a thunderstorm after midnight. Mostly cloudy, with a low around 63. South wind 11 to 14 mph, with gusts as high as 24 mph. Chance of precipitation is 70%.

    Low: 63 °F

    Mostly Cloudy
    then Showers
    Likely

  • Saturday

    Saturday: Showers and possibly a thunderstorm before noon, then a chance of showers and thunderstorms after noon. High near 72. South southwest wind 10 to 14 mph becoming northwest in the afternoon. Winds could gust as high as 23 mph. Chance of precipitation is 80%.

    High: 72 °F

    Showers then
    Chance
    T-storms

  • Saturday Night

    Saturday Night: A 20 percent chance of showers before midnight. Partly cloudy, with a low around 41. Northwest wind 5 to 9 mph becoming calm after midnight.

    Low: 41 °F

    Slight Chance
    Showers then
    Partly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 65. Calm wind becoming southwest around 6 mph.

    High: 65 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Mostly clear, with a low around 49. South wind 3 to 6 mph.

    Low: 49 °F

    Mostly Clear

  • Monday

    Monday: Sunny, with a high near 75. South southwest wind 6 to 13 mph, with gusts as high as 20 mph.

    High: 75 °F

    Sunny

Detailed Forecast

This Afternoon
A 40 percent chance of showers and thunderstorms, mainly between 1pm and 4pm. Mostly cloudy, with a steady temperature around 67. Southwest wind 5 to 10 mph becoming light west.
Tonight
A chance of showers and thunderstorms. Mostly cloudy, with a low around 59. Calm wind becoming south southeast around 6 mph after midnight. Chance of precipitation is 40%.
Friday
A 20 percent chance of showers before 8am. Mostly sunny, with a high near 76. South wind 7 to 17 mph, with gusts as high as 25 mph.
Friday Night
Showers likely and possibly a thunderstorm after midnight. Mostly cloudy, with a low around 63. South wind 11 to 14 mph, with gusts as high as 24 mph. Chance of precipitation is 70%.
Saturday
Showers and possibly a thunderstorm before noon, then a chance of showers and thunderstorms after noon. High near 72. South southwest wind 10 to 14 mph becoming northwest in the afternoon. Winds could gust as high as 23 mph. Chance of precipitation is 80%.
Saturday Night
A 20 percent chance of showers before midnight. Partly cloudy, with a low around 41. Northwest wind 5 to 9 mph becoming calm after midnight.
Sunday
Mostly sunny, with a high near 65. Calm wind becoming southwest around 6 mph.
Sunday Night
Mostly clear, with a low around 49. South wind 3 to 6 mph.
Monday
Sunny, with a high near 75. South southwest wind 6 to 13 mph, with gusts as high as 20 mph.
Monday Night
A slight chance of showers, then a chance of showers and thunderstorms after midnight. Partly cloudy, with a low around 60. South southwest wind around 10 mph, with gusts as high as 18 mph.
Tuesday
Showers likely and possibly a thunderstorm. Partly sunny, with a high near 76. South southwest wind 9 to 16 mph, with gusts as high as 24 mph.
Tuesday Night
Showers and possibly a thunderstorm. Mostly cloudy, with a low around 59. South wind around 15 mph, with gusts as high as 25 mph.
Wednesday
Showers. Mostly cloudy, with a high near 70. South southwest wind 14 to 16 mph becoming north northwest in the afternoon. Winds could gust as high as 24 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:
10:51 am CST Mar 5, 2026
Forecast Valid:
12pm CST Mar 5, 2026-6pm CDT Mar 11, 2026
 
Forecast Discussion
 
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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