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Hazardous Weather Conditions
Current conditions at
Southern Illinois Airport (KMDH)
Lat: 37.78°NLon: 89.25°WElev: 400ft.
Fair
79°F
26°C
| Humidity | 82% |
| Wind Speed | SE 5 mph |
| Barometer | 30.02 in (1016.1 mb) |
| Dewpoint | 73°F (23°C) |
| Visibility | 10.00 mi |
| Heat Index | 82°F (28°C) |
| Last update | 18 Aug 10:52 pm CDT |
Extended Forecast for
Saint Johns IL
Heat Advisory August 18, 11:43pm until August 19, 07:00pm
NOW until 7:00pm Tue
Heat Advisory
Tonight
Low: 75 °F
Clear
Tuesday
High: 98 °F
Chance
T-stormsTuesday Night
Low: 72 °F
Chance
T-stormsWednesday
High: 90 °F
Chance
T-stormsWednesday Night
Low: 68 °F
Partly Cloudy
Thursday
High: 89 °F
Mostly Sunny
Thursday Night
Low: 66 °F
Mostly Clear
Friday
High: 91 °F
Sunny
Detailed Forecast
Tonight
Clear, with a low around 75. Calm wind.
Tuesday
A slight chance of showers, then a chance of showers and thunderstorms after 10am. Sunny and hot, with a high near 98. Heat index values as high as 109. Calm wind becoming northwest around 6 mph in the afternoon. Chance of precipitation is 30%.
Tuesday Night
A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 72. Light north wind.
Wednesday
A 30 percent chance of showers and thunderstorms, mainly before 1pm. Mostly sunny, with a high near 90. Light north northeast wind increasing to 5 to 10 mph in the morning.
Wednesday Night
Partly cloudy, with a low around 68. North northeast wind 6 to 9 mph.
Thursday
Mostly sunny, with a high near 89. North northeast wind 6 to 10 mph.
Thursday Night
Mostly clear, with a low around 66. North northeast wind 5 to 7 mph becoming calm in the evening.
Friday
Sunny, with a high near 91. Calm wind becoming north around 6 mph in the afternoon.
Friday Night
Mostly clear, with a low around 67. North wind around 5 mph becoming calm in the evening.
Saturday
Sunny, with a high near 91. Calm wind becoming north northwest 5 to 8 mph in the afternoon.
Saturday Night
Mostly clear, with a low around 63. North wind 3 to 6 mph.
Sunday
Sunny, with a high near 85. Light north wind becoming north northwest 5 to 10 mph in the morning.
Sunday Night
Mostly clear, with a low around 59. North wind 3 to 7 mph.
Monday
Sunny, with a high near 81. North northwest wind 3 to 7 mph.
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Forecast AreaABOUT THIS FORECAST
Point Forecast:
Saint Johns IL
38.03°N 89.24°W
38.03°N 89.24°W
11:31 pm CDT Aug 18, 2025
11pm CDT Aug 18, 2025-6pm CDT Aug 25, 2025
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