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Hazardous Weather Conditions
Current conditions at
Southern Illinois Airport (KMDH)
Lat: 37.78°NLon: 89.25°WElev: 400ft.
Fog/Mist
74°F
23°C
| Humidity | 97% |
| Wind Speed | Calm |
| Barometer | 30.01 in (1015.6 mb) |
| Dewpoint | 73°F (23°C) |
| Visibility | 5.00 mi |
| Last update | 18 Aug 1:52 am CDT |
Extended Forecast for
Saint Johns IL
Heat Advisory August 18, 02:19am until August 19, 07:00pm
NOW until 7:00pm Tue
Heat Advisory
Overnight
Low: 74 °F
Partly Cloudy
Monday
High: 98 °F
Sunny then
Slight Chance
T-stormsMonday Night
Low: 74 °F
Mostly Clear
Tuesday
High: 97 °F
Chance
T-stormsTuesday Night
Low: 73 °F
Chance
T-stormsWednesday
High: 92 °F
Chance
T-stormsWednesday Night
Low: 66 °F
Partly Cloudy
Thursday
High: 89 °F
Sunny
Detailed Forecast
Overnight
Partly cloudy, with a low around 74. Calm wind.
Monday
A 20 percent chance of showers and thunderstorms after 4pm. Sunny and hot, with a high near 98. Heat index values as high as 105. Calm wind becoming south southeast around 5 mph.
Monday Night
Mostly clear, with a low around 74. East southeast wind around 5 mph becoming calm in the evening.
Tuesday
A 30 percent chance of showers and thunderstorms, mainly after 1pm. Mostly sunny and hot, with a high near 97. Calm wind becoming northwest around 6 mph in the afternoon.
Tuesday Night
A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 73. Light north northwest wind.
Wednesday
A 30 percent chance of showers and thunderstorms. Mostly sunny, with a high near 92. Light north wind increasing to 5 to 10 mph in the morning.
Wednesday Night
Partly cloudy, with a low around 66. North northeast wind 6 to 9 mph.
Thursday
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 8 mph becoming calm in the evening.
Friday
Sunny, with a high near 91. Calm wind becoming north northeast around 6 mph in the morning.
Friday Night
Mostly clear, with a low around 65. North wind around 5 mph becoming calm in the evening.
Saturday
Sunny, with a high near 91. Calm wind becoming north northwest 5 to 7 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 86. Light north wind becoming north northwest 5 to 9 mph in the morning.
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Forecast AreaABOUT THIS FORECAST
Point Forecast:
Saint Johns IL
38.06°N 89.24°W
38.06°N 89.24°W
1:45 am CDT Aug 18, 2025
2am CDT Aug 18, 2025-6pm CDT Aug 24, 2025
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