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

Dangerous Heat and Possible Flooding This Week

Hot temperatures and high humidity are forecast to continue across much of east Texas into the mid-Mississippi Valley through this week. Heavy to excessive rainfall occurring at times through Friday could bring areas of flooding across parts of the central Plains into the upper Midwest and Four Corners states. Read More >

Hazardous Weather Conditions

Current conditions at

Chicago/Waukegan Regional Airport (KUGN)

Lat: 42.43°NLon: 87.86°WElev: 709ft.

Mostly Cloudy

67°F

19°C

Humidity 63%
Wind Speed S 15 G 28 mph
Barometer 30.02 in (1015.8 mb)
Dewpoint 54°F (12°C)
Visibility 10.00 mi
Last update 14 Sep 10:51 pm CDT
Extended Forecast for

Grayslake IL

  • Tonight

    Tonight: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 4am. Mostly cloudy, with a low around 64. South southwest wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    Low: 64 °F

    Showers
    Likely

  • Tuesday

    Tuesday: Showers and possibly a thunderstorm, mainly before 10am, then a chance of showers and thunderstorms after 10am. High near 77. South southwest wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    High: 77 °F

    Showers then
    Chance
    T-storms

  • Tuesday Night

    Tuesday Night: A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers and thunderstorms after 4am. Mostly cloudy, with a low around 60. West northwest wind 5 to 10 mph becoming north after midnight. Chance of precipitation is 20%.

    Low: 60 °F

    Slight Chance
    T-storms

  • Wednesday

    Wednesday: A 50 percent chance of showers and thunderstorms, mainly after 7am. Mostly cloudy, with a high near 70. East northeast wind 5 to 10 mph.

    High: 70 °F

    Chance
    T-storms

  • Wednesday Night

    Wednesday Night: A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 65. East northeast wind around 5 mph becoming calm after midnight. Chance of precipitation is 60%.

    Low: 65 °F

    Chance
    T-storms then
    Showers
    Likely

  • Thursday

    Thursday: Showers likely and possibly a thunderstorm before 1pm. Mostly cloudy, with a high near 75. Chance of precipitation is 60%.

    High: 75 °F

    Showers
    Likely

  • Thursday Night

    Thursday Night: A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 63.

    Low: 63 °F

    Mostly Cloudy
    then Chance
    Showers

  • Friday

    Friday: A chance of showers before 1pm. Mostly cloudy, with a high near 77.

    High: 77 °F

    Chance
    Showers

  • Friday Night

    Friday Night: A chance of showers. Mostly cloudy, with a low around 66.

    Low: 66 °F

    Chance
    Showers

Detailed Forecast

Tonight
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 4am. Mostly cloudy, with a low around 64. South southwest wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 70%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Tuesday
Showers and possibly a thunderstorm, mainly before 10am, then a chance of showers and thunderstorms after 10am. High near 77. South southwest wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Tuesday Night
A slight chance of showers and thunderstorms before 10pm, then a slight chance of showers and thunderstorms after 4am. Mostly cloudy, with a low around 60. West northwest wind 5 to 10 mph becoming north after midnight. Chance of precipitation is 20%.
Wednesday
A 50 percent chance of showers and thunderstorms, mainly after 7am. Mostly cloudy, with a high near 70. East northeast wind 5 to 10 mph.
Wednesday Night
A chance of showers and thunderstorms, then showers likely and possibly a thunderstorm after 1am. Mostly cloudy, with a low around 65. East northeast wind around 5 mph becoming calm after midnight. Chance of precipitation is 60%.
Thursday
Showers likely and possibly a thunderstorm before 1pm. Mostly cloudy, with a high near 75. Chance of precipitation is 60%.
Thursday Night
A 30 percent chance of showers after 1am. Mostly cloudy, with a low around 63.
Friday
A chance of showers before 1pm. Mostly cloudy, with a high near 77.
Friday Night
A chance of showers. Mostly cloudy, with a low around 66.
Saturday
A chance of showers, then showers likely and possibly a thunderstorm after 1pm. Mostly sunny, with a high near 81.
Saturday Night
A chance of showers. Mostly cloudy, with a low around 63.
Sunday
A chance of showers. Mostly cloudy, with a high near 75.
Sunday Night
A chance of showers. Mostly cloudy, with a low around 59.
Monday
A chance of showers. Partly sunny, with a high near 73.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Grayslake IL
 42.35°N 88.02°W
Last Update:
9:11 pm CDT Sep 14, 2026
Forecast Valid:
11pm CDT Sep 14, 2026-6pm CDT Sep 21, 2026
 
Forecast Discussion
 
Get as KML Get as XML

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