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

Widespread Showers in the Eastern US; Severe Thunderstorms in the Plains; Heatwave in the Desert Southwest

Widespread showers and thunderstorms across much of the central and eastern U.S. will produce areas of excessive rainfall, especially in the southern Mid-Atlantic states. Scattered severe thunderstorms are expected from Montana into portions of the central/southern Plains this weekend. A heatwave will build in the Desert Southwest, in parts of Arizona, southeastern California, and southern Nevada. Read More >

Current conditions at

Decatur Airport (KDEC)

Lat: 39.83°NLon: 88.87°WElev: 670ft.

Overcast

72°F

22°C

Humidity 84%
Wind Speed NE 10 mph
Barometer 29.99 in (1015.0 mb)
Dewpoint 67°F (19°C)
Visibility 8.00 mi
Last update 14 Jun 10:54 am CDT
Extended Forecast for

Illiopolis IL

  • Today

    Today: Mostly cloudy, with a high near 79. North northeast wind around 9 mph.

    High: 79 °F

    Mostly Cloudy

  • Tonight

    Tonight: Partly cloudy, with a low around 63. North northeast wind 5 to 8 mph.

    Low: 63 °F

    Partly Cloudy

  • Sunday

    Sunday: Mostly sunny, with a high near 83. East northeast wind around 7 mph.

    High: 83 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 66. East wind 3 to 5 mph.

    Low: 66 °F

    Partly Cloudy

  • Monday

    Monday: A 30 percent chance of showers after 1pm. Partly sunny, with a high near 84. Southeast wind around 6 mph.

    High: 84 °F

    Partly Sunny
    then Chance
    Showers

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 68. South wind around 6 mph.

    Low: 68 °F

    Mostly Cloudy

  • Tuesday

    Tuesday: A 40 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 87. South southwest wind 6 to 10 mph.

    High: 87 °F

    Partly Sunny
    then Chance
    T-storms

  • Tuesday Night

    Tuesday Night: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 72.

    Low: 72 °F

    Chance
    T-storms

  • Wednesday

    Wednesday: Showers and thunderstorms likely, mainly after 1pm. Mostly cloudy, with a high near 85. Chance of precipitation is 70%.

    High: 85 °F

    Chance
    T-storms then
    T-storms
    Likely

Detailed Forecast

Today
Mostly cloudy, with a high near 79. North northeast wind around 9 mph.
Tonight
Partly cloudy, with a low around 63. North northeast wind 5 to 8 mph.
Sunday
Mostly sunny, with a high near 83. East northeast wind around 7 mph.
Sunday Night
Partly cloudy, with a low around 66. East wind 3 to 5 mph.
Monday
A 30 percent chance of showers after 1pm. Partly sunny, with a high near 84. Southeast wind around 6 mph.
Monday Night
Mostly cloudy, with a low around 68. South wind around 6 mph.
Tuesday
A 40 percent chance of showers and thunderstorms after 1pm. Mostly sunny, with a high near 87. South southwest wind 6 to 10 mph.
Tuesday Night
A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 72.
Wednesday
Showers and thunderstorms likely, mainly after 1pm. Mostly cloudy, with a high near 85. Chance of precipitation is 70%.
Wednesday Night
A 50 percent chance of showers and thunderstorms before 1am. Mostly cloudy, with a low around 69.
Juneteenth
Mostly sunny, with a high near 84.
Thursday Night
Mostly clear, with a low around 66.
Friday
Mostly sunny, with a high near 86.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Illiopolis IL
 39.85°N 89.26°W (Elev. 607 ft)
Last Update:
9:56 am CDT Jun 14, 2025
Forecast Valid:
11am CDT Jun 14, 2025-6pm CDT Jun 20, 2025
 
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