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Watching Hurricane Erin; Heavy Rainfall Threat for Upper Midwest; Heatrisk for Mississippi Valley

Hurricane Erin continues to track westward with its outer bands bringing heavy rainfall and gusty winds for Puerto Rico and US Virgin Islands. Life-threatening surf and rip currents are occurring and will spread across the Atlantic coasts this week. Meanwhile, heavy rainfall and possible flooding are in the forecast for upper Midwest through Monday. Heatrisk continues for the Mississippi Valley. Read More >

Hazardous Weather Conditions

Current conditions at

Chicago/Waukegan Regional Airport (KUGN)

Lat: 42.43°NLon: 87.86°WElev: 709ft.

Mostly Cloudy

79°F

26°C

Humidity 69%
Wind Speed NE 13 G 20 mph
Barometer 30.09 in (1017.9 mb)
Dewpoint 68°F (20°C)
Visibility 10.00 mi
Heat Index81°F (27°C)
Last update 17 Aug 12:51 pm CDT
Extended Forecast for

McHenry IL

  • This Afternoon

    This Afternoon: Partly sunny, with a high near 78. East northeast wind around 10 mph.

    High: 78 °F

    Partly Sunny

  • Tonight

    Tonight: Partly cloudy, with a low around 67. Northeast wind 5 to 10 mph.

    Low: 67 °F

    Partly Cloudy

  • Monday

    Monday: A 40 percent chance of showers and thunderstorms. Mostly sunny, with a high near 88. South wind around 10 mph, with gusts as high as 15 mph.

    High: 88 °F

    Chance
    T-storms

  • Monday Night

    Monday Night: Showers and thunderstorms likely, mainly after 1am. Mostly cloudy, with a low around 70. South wind around 5 mph, with gusts as high as 15 mph. Chance of precipitation is 60%.

    Low: 70 °F

    T-storms
    Likely

  • Tuesday

    Tuesday: A 30 percent chance of showers and thunderstorms, mainly before 1pm. Partly sunny, with a high near 86. Southwest wind 5 to 10 mph becoming northwest in the afternoon.

    High: 86 °F

    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: Mostly cloudy, with a low around 64.

    Low: 64 °F

    Mostly Cloudy

  • Wednesday

    Wednesday: Partly sunny, with a high near 77.

    High: 77 °F

    Partly Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 62.

    Low: 62 °F

    Partly Cloudy

  • Thursday

    Thursday: Sunny, with a high near 80.

    High: 80 °F

    Sunny

Detailed Forecast

This Afternoon
Partly sunny, with a high near 78. East northeast wind around 10 mph.
Tonight
Partly cloudy, with a low around 67. Northeast wind 5 to 10 mph.
Monday
A 40 percent chance of showers and thunderstorms. Mostly sunny, with a high near 88. South wind around 10 mph, with gusts as high as 15 mph.
Monday Night
Showers and thunderstorms likely, mainly after 1am. Mostly cloudy, with a low around 70. South wind around 5 mph, with gusts as high as 15 mph. Chance of precipitation is 60%.
Tuesday
A 30 percent chance of showers and thunderstorms, mainly before 1pm. Partly sunny, with a high near 86. Southwest wind 5 to 10 mph becoming northwest in the afternoon.
Tuesday Night
Mostly cloudy, with a low around 64.
Wednesday
Partly sunny, with a high near 77.
Wednesday Night
Partly cloudy, with a low around 62.
Thursday
Sunny, with a high near 80.
Thursday Night
Mostly clear, with a low around 60.
Friday
Sunny, with a high near 84.
Friday Night
Mostly clear, with a low around 62.
Saturday
Mostly sunny, with a high near 80.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
McHenry IL
 42.34°N 88.26°W
Last Update:
1:14 pm CDT Aug 17, 2025
Forecast Valid:
1pm CDT Aug 17, 2025-6pm CDT Aug 23, 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