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.

Mostly Cloudy

69°F

21°C

Humidity 90%
Wind Speed S 15 G 22 mph
Barometer 29.94 in (1013.4 mb)
Dewpoint 66°F (19°C)
Visibility 8.00 mi
Last update 10 Mar 8:52 am CDT
Extended Forecast for

Saint Johns IL

  • Today

    Today: Mostly cloudy, with a high near 79. South southwest wind 9 to 17 mph, with gusts as high as 26 mph.

    High: 79 °F

    Mostly Cloudy

  • Tonight

    Tonight: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 5am. Cloudy, with a low around 65. South southwest wind 15 to 17 mph, with gusts as high as 28 mph. Chance of precipitation is 60%.

    Low: 65 °F

    Slight Chance
    T-storms then
    Showers
    Likely

  • Wednesday

    Wednesday: Showers and thunderstorms before 1pm, then showers likely and possibly a thunderstorm between 1pm and 4pm, then showers likely after 4pm. Temperature falling to around 51 by 5pm. Breezy, with a south southwest wind 15 to 21 mph becoming northwest in the afternoon. Winds could gust as high as 29 mph. Chance of precipitation is 90%.

    High: 70 °F⇓

    Showers and
    Breezy

  • Wednesday Night

    Wednesday Night: A 30 percent chance of showers before 7pm. Mostly cloudy, with a low around 34. Breezy, with a north northwest wind 15 to 20 mph decreasing to 8 to 13 mph after midnight. Winds could gust as high as 29 mph.

    Low: 34 °F

    Chance
    Showers and
    Breezy then
    Mostly Cloudy

  • Thursday

    Thursday: Sunny, with a high near 54. North northwest wind around 6 mph becoming west southwest in the afternoon.

    High: 54 °F

    Sunny

  • Thursday Night

    Thursday Night: Partly cloudy, with a low around 43. South wind 7 to 12 mph increasing to 13 to 18 mph after midnight. Winds could gust as high as 29 mph.

    Low: 43 °F

    Partly Cloudy

  • Friday

    Friday: Partly sunny, with a high near 64. Southwest wind 9 to 16 mph, with gusts as high as 28 mph.

    High: 64 °F

    Partly Sunny

  • Friday Night

    Friday Night: Partly cloudy, with a low around 40. North northwest wind around 6 mph becoming east after midnight.

    Low: 40 °F

    Partly Cloudy

  • Saturday

    Saturday: Sunny, with a high near 68. East southeast wind 7 to 14 mph becoming south in the afternoon. Winds could gust as high as 22 mph.

    High: 68 °F

    Sunny

Detailed Forecast

Today
Mostly cloudy, with a high near 79. South southwest wind 9 to 17 mph, with gusts as high as 26 mph.
Tonight
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 5am. Cloudy, with a low around 65. South southwest wind 15 to 17 mph, with gusts as high as 28 mph. Chance of precipitation is 60%.
Wednesday
Showers and thunderstorms before 1pm, then showers likely and possibly a thunderstorm between 1pm and 4pm, then showers likely after 4pm. Temperature falling to around 51 by 5pm. Breezy, with a south southwest wind 15 to 21 mph becoming northwest in the afternoon. Winds could gust as high as 29 mph. Chance of precipitation is 90%.
Wednesday Night
A 30 percent chance of showers before 7pm. Mostly cloudy, with a low around 34. Breezy, with a north northwest wind 15 to 20 mph decreasing to 8 to 13 mph after midnight. Winds could gust as high as 29 mph.
Thursday
Sunny, with a high near 54. North northwest wind around 6 mph becoming west southwest in the afternoon.
Thursday Night
Partly cloudy, with a low around 43. South wind 7 to 12 mph increasing to 13 to 18 mph after midnight. Winds could gust as high as 29 mph.
Friday
Partly sunny, with a high near 64. Southwest wind 9 to 16 mph, with gusts as high as 28 mph.
Friday Night
Partly cloudy, with a low around 40. North northwest wind around 6 mph becoming east after midnight.
Saturday
Sunny, with a high near 68. East southeast wind 7 to 14 mph becoming south in the afternoon. Winds could gust as high as 22 mph.
Saturday Night
Partly cloudy, with a low around 55. South wind 11 to 14 mph, with gusts as high as 25 mph.
Sunday
Showers and thunderstorms likely. Mostly cloudy, with a high near 66. Breezy, with a south southwest wind 15 to 20 mph becoming west northwest in the afternoon. Winds could gust as high as 30 mph.
Sunday Night
A chance of rain and snow showers. Mostly cloudy, with a low around 25. Blustery, with a northwest wind 16 to 21 mph, with gusts as high as 29 mph.
Monday
A slight chance of snow showers. Mostly sunny, with a high near 38. Northwest wind around 14 mph, with gusts as high as 22 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:
8:01 am CDT Mar 10, 2026
Forecast Valid:
9am CDT Mar 10, 2026-6pm CDT Mar 16, 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