Chicago Nearshore Marine Forecasts by Zone

 
 

 
 
 
 
 
FORECAST For Wilmette Harbor to Northerly Island (LMZ741)
 
 
 
 
 LMZ740>742-310345-
 Winthrop Harbor to Wilmette Harbor IL-
 Wilmette Harbor to Northerly Island IL-
 Northerly Island to Calumet Harbor IL-
 254 PM CDT Thu Jul 30 2026
 

 TONIGHT
 Southeast winds around 10 kt becoming southwest late.
 Mostly cloudy. Waves 1 ft or less.

 FRIDAY
 South winds 10 to 15 kt becoming southeast in the
 afternoon. Chance of showers in the afternoon. Waves 1 ft or less
 building to 1 to 2 ft.

 FRIDAY NIGHT
 Southeast winds 15 to 20 kt becoming east and
 increasing to 20 to 25 kt. Showers and slight chance of
 thunderstorms in the evening, then showers and a chance of
 thunderstorms overnight. Waves 1 to 3 ft building to 4 to 6 ft
 occasionally to 8 ft. A small craft advisory will likely be
 needed.

 SATURDAY
 East winds 20 to 25 kt becoming northeast in the
 afternoon. Showers and a chance of thunderstorms in the morning,
 then showers likely and slight chance of thunderstorms in the
 afternoon. Waves 4 to 7 ft occasionally to 9 ft.
 
 $$