Hazardous Weather Conditions
Current conditions at
Southern Illinois Airport (KMDH)
Lat: 37.78°NLon: 89.25°WElev: 400ft.
Fog/Mist
35°F
2°C
| Humidity | 100% |
| Wind Speed | Calm |
| Barometer | 30.05 in (1017.7 mb) |
| Dewpoint | 35°F (2°C) |
| Visibility | 2.50 mi |
| Last update | 15 Feb 10:52 pm CST |
Extended Forecast for
Saint Johns IL
Dense Fog Advisory until February 16, 09:00am
NOW until 9:00am Mon
Dense Fog Advisory
Tonight
Low: 34 °F
Dense Fog
Washington's Birthday
High: 62 °F
Dense Fog
then Mostly
SunnyMonday Night
Low: 42 °F
Mostly Cloudy
Tuesday
High: 63 °F
Mostly Cloudy
Tuesday Night
Low: 58 °F
Mostly Cloudy
and BreezyWednesday
High: 73 °F
Mostly Sunny
Wednesday Night
Low: 50 °F
Mostly Clear
Thursday
High: 72 °F
Mostly Sunny
then Slight
Chance
T-storms
Detailed Forecast
Tonight
Widespread dense fog, mainly after midnight. Otherwise, mostly cloudy, with a low around 34. Calm wind.
Washington's Birthday
Widespread dense fog before 9am. Otherwise, mostly sunny, with a high near 62. Light south southwest wind increasing to 5 to 10 mph in the morning.
Monday Night
Mostly cloudy, with a low around 42. South wind 5 to 7 mph.
Tuesday
Mostly cloudy, with a high near 63. South wind 7 to 17 mph, with gusts as high as 26 mph.
Tuesday Night
Mostly cloudy, with a low around 58. Breezy, with a south southwest wind 18 to 22 mph, with gusts as high as 33 mph.
Wednesday
Mostly sunny, with a high near 73. Southwest wind 10 to 18 mph, with gusts as high as 29 mph.
Wednesday Night
Mostly clear, with a low around 50. South southwest wind 6 to 9 mph.
Thursday
A slight chance of showers and thunderstorms after noon. Mostly sunny, with a high near 72. South wind 6 to 14 mph, with gusts as high as 22 mph.
Thursday Night
A chance of showers and thunderstorms before midnight, then a slight chance of showers. Partly cloudy, with a low around 43. South southwest wind 8 to 10 mph becoming west after midnight. Winds could gust as high as 20 mph.
Friday
A chance of showers, mainly after noon. Partly sunny, with a high near 56. West northwest wind 8 to 10 mph.
Friday Night
A chance of showers. Mostly cloudy, with a low around 33. North northwest wind around 7 mph.
Saturday
A slight chance of showers. Partly sunny, with a high near 50. North northwest wind 6 to 9 mph.
Saturday Night
A slight chance of showers. Partly cloudy, with a low around 29. North northwest wind around 7 mph.
Sunday
Mostly sunny, with a high near 46. Northwest wind 7 to 10 mph.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast AreaABOUT THIS FORECAST
Point Forecast:
Saint Johns IL
38.03°N 89.24°W
38.03°N 89.24°W
8:42 pm CST Feb 15, 2026
11pm CST Feb 15, 2026-6pm CST Feb 22, 2026
Additional Resources
Radar & Satellite Image
Hourly Weather Forecast
