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

Dangerous Heat and Heavy Rainfall into the Weekend

Hot temperatures and high humidity are forecast to continue across the mid-Mississippi Valley into this weekend. Heat Advisories remain in effect. Heavy to excessive rainfall occurring at times through the weekend could bring areas of flooding to parts of the northern Rockies, upper Midwest, central Great Lakes, and southern New England. Read More >

Hazardous Weather Conditions

Current conditions at

Chicago/Waukegan Regional Airport (KUGN)

Lat: 42.43°NLon: 87.86°WElev: 709ft.

Thunderstorm Light Rain

65°F

18°C

Humidity 90%
Wind Speed NE 13 mph
Barometer 30.02 in (1015.9 mb)
Dewpoint 62°F (17°C)
Visibility 9.00 mi
Last update 19 Sep 3:51 am CDT
Extended Forecast for

Winthrop Harbor IL

Flood Watch until September 19, 01:00pm
Flood Advisory until September 19, 09:00am
Click here for hazard details and duration
Flood Watch
Flood Advisory
  •  
    Flood Watch until September 19, 01:00pm
    Flood Advisory until September 19, 09:00am

    NOW: Multiple hazards in effect

    Click HERE for Details

  • Overnight

    Low: 65 °F

    Heavy Rain
    and Breezy

  • Saturday

    Saturday: Showers and thunderstorms, mainly before 1pm, then showers likely and possibly a thunderstorm after 4pm. Some of the storms could produce heavy rainfall. High near 73. Breezy, with a south southeast wind 10 to 20 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.

    High: 73 °F

    Heavy Rain
    and Breezy
    then T-storms
    Likely

  • Saturday Night

    Saturday Night: Showers and thunderstorms, mainly before 4am. Some of the storms could produce heavy rainfall. Low around 60. South southeast wind 5 to 15 mph becoming north northeast after midnight. Chance of precipitation is 90%. New rainfall amounts between 1 and 2 inches possible.

    Low: 60 °F

    Heavy Rain

  • Sunday

    Sunday: A chance of showers and thunderstorms. Cloudy, with a high near 68. Breezy, with a northeast wind 20 to 25 mph, with gusts as high as 30 mph. Chance of precipitation is 40%.

    High: 68 °F

    Breezy.
    Chance
    T-storms then
    Slight Chance
    Showers

  • Sunday Night

    Sunday Night: Mostly cloudy, with a low around 55. Breezy, with an east northeast wind 20 to 25 mph, with gusts as high as 30 mph.

    Low: 55 °F

    Mostly Cloudy
    and Breezy

  • Monday

    Monday: A 20 percent chance of showers before 1pm. Mostly cloudy, with a high near 65. Breezy.

    High: 65 °F

    Slight Chance
    Showers and
    Breezy

  • Monday Night

    Monday Night: Mostly cloudy, with a low around 53. Breezy.

    Low: 53 °F

    Mostly Cloudy
    and Breezy

  • Tuesday

    Tuesday: Mostly cloudy, with a high near 64. Breezy.

    High: 64 °F

    Mostly Cloudy
    and Breezy

Detailed Forecast

Overnight
Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Steady temperature around 65. Breezy, with an east southeast wind around 20 mph. Chance of precipitation is 100%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Saturday
Showers and thunderstorms, mainly before 1pm, then showers likely and possibly a thunderstorm after 4pm. Some of the storms could produce heavy rainfall. High near 73. Breezy, with a south southeast wind 10 to 20 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.
Saturday Night
Showers and thunderstorms, mainly before 4am. Some of the storms could produce heavy rainfall. Low around 60. South southeast wind 5 to 15 mph becoming north northeast after midnight. Chance of precipitation is 90%. New rainfall amounts between 1 and 2 inches possible.
Sunday
A chance of showers and thunderstorms. Cloudy, with a high near 68. Breezy, with a northeast wind 20 to 25 mph, with gusts as high as 30 mph. Chance of precipitation is 40%.
Sunday Night
Mostly cloudy, with a low around 55. Breezy, with an east northeast wind 20 to 25 mph, with gusts as high as 30 mph.
Monday
A 20 percent chance of showers before 1pm. Mostly cloudy, with a high near 65. Breezy.
Monday Night
Mostly cloudy, with a low around 53. Breezy.
Tuesday
Mostly cloudy, with a high near 64. Breezy.
Tuesday Night
Mostly cloudy, with a low around 53.
Wednesday
Partly sunny, with a high near 65.
Wednesday Night
Mostly cloudy, with a low around 53.
Thursday
Partly sunny, with a high near 66.
Thursday Night
Mostly cloudy, with a low around 54.
Friday
Mostly sunny, with a high near 68.
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Forecast Area
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ABOUT THIS FORECAST

 
Point Forecast:
Winthrop Harbor IL
 42.47°N 87.81°W
Last Update:
3:46 am CDT Sep 19, 2026
Forecast Valid:
5am CDT Sep 19, 2026-6pm CDT Sep 25, 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