National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Dangerous Heat in the Central and Eastern U.S.; Critical Fire Weather in the Great Basin and Southwest

Dangerous, record-breaking heat will intensify across most of the central and eastern U.S this week. Heat indices will likely exceed 100 degrees. Heat is likely to continue across the eastern U.S. through the Independence Day holiday weekend. Critical fire weather conditions will continue Tuesday across portions of the Four Corners and Great Basin, as dry conditions and gusty winds persist. Read More >

Hazardous Weather Conditions

Current conditions at

Southern Illinois Airport (KMDH)

Lat: 37.78°NLon: 89.25°WElev: 400ft.

Fair

83°F

28°C

Humidity 79%
Wind Speed S 8 mph
Barometer 29.98 in (1014.8 mb)
Dewpoint 76°F (24°C)
Visibility 10.00 mi
Heat Index91°F (33°C)
Last update 29 Jun 8:52 pm CDT
Extended Forecast for

3 Miles NW Royalton IL

Extreme Heat Warning June 29, 09:11pm until July 3, 08:00pm
Click here for hazard details and duration
Extreme Heat Warning
  •  
    Extreme Heat Warning June 29, 09:11pm until July 3, 08:00pm

    NOW until 8:00pm Fri

    Extreme Heat Warning

  • Tonight

    Low: 75 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny, with a high near 96. Heat index values as high as 110. South southwest wind 3 to 8 mph.

    High: 96 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Clear, with a low around 74. South wind 5 to 7 mph becoming calm in the evening.

    Low: 74 °F

    Clear

  • Wednesday

    Wednesday: Sunny, with a high near 96. Heat index values as high as 109. Calm wind becoming south southwest 5 to 7 mph in the afternoon.

    High: 96 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 76. South wind around 5 mph becoming calm in the evening.

    Low: 76 °F

    Mostly Clear

  • Thursday

    Thursday: Sunny, with a high near 96. Calm wind becoming south around 6 mph in the afternoon.

    High: 96 °F

    Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 76. Light and variable wind.

    Low: 76 °F

    Mostly Clear

  • Friday

    Friday: A slight chance of showers and thunderstorms after 1pm. Sunny, with a high near 94. Calm wind becoming south around 5 mph in the afternoon.

    High: 94 °F

    Sunny then
    Slight Chance
    T-storms

Detailed Forecast

Tonight
Mostly clear, with a low around 75. South wind 3 to 7 mph.
Tuesday
Sunny, with a high near 96. Heat index values as high as 110. South southwest wind 3 to 8 mph.
Tuesday Night
Clear, with a low around 74. South wind 5 to 7 mph becoming calm in the evening.
Wednesday
Sunny, with a high near 96. Heat index values as high as 109. Calm wind becoming south southwest 5 to 7 mph in the afternoon.
Wednesday Night
Mostly clear, with a low around 76. South wind around 5 mph becoming calm in the evening.
Thursday
Sunny, with a high near 96. Calm wind becoming south around 6 mph in the afternoon.
Thursday Night
Mostly clear, with a low around 76. Light and variable wind.
Friday
A slight chance of showers and thunderstorms after 1pm. Sunny, with a high near 94. Calm wind becoming south around 5 mph in the afternoon.
Friday Night
Mostly clear, with a low around 75. Light and variable wind.
Independence Day
A slight chance of showers and thunderstorms. Mostly sunny, with a high near 93. Calm wind.
Saturday Night
Partly cloudy, with a low around 75. Calm wind.
Sunday
A chance of showers and thunderstorms. Mostly sunny, with a high near 92. Calm wind becoming southwest around 5 mph in the afternoon.
Sunday Night
A chance of showers and thunderstorms. Partly cloudy, with a low around 74. Light west wind.
Monday
A chance of showers and thunderstorms. Mostly sunny, with a high near 90. Calm wind becoming west around 6 mph in the afternoon.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
3 Miles NW Royalton IL
 37.92°N 89.16°W
Last Update:
8:41 pm CDT Jun 29, 2026
Forecast Valid:
9pm CDT Jun 29, 2026-6pm CDT Jul 6, 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