Chicago Nearshore Marine Forecasts by Zone

 
 

 
 
 
 
 
FORECAST For Wilmette Harbor to Northerly Island (LMZ741)
 
 
 
 
 LMZ740>742-210915-
 Winthrop Harbor to Wilmette Harbor IL-
 Wilmette Harbor to Northerly Island IL-
 Northerly Island to Calumet Harbor IL-
 838 PM CDT Mon Jul 20 2026
 
 SMALL CRAFT ADVISORY IN EFFECT UNTIL 6 AM CDT TUESDAY
 

 REST OF TONIGHT
 Southwest winds 15 to 20 kt increasing to 20
 to 25 kt late in the evening, then becoming west late. Chance of
 showers and thunderstorms after midnight. Waves 1 to 3 ft.

 TUESDAY
 West winds 10 to 20 kt becoming northwest in the
 afternoon and increasing to 15 to 25 kt late. Mostly sunny in the
 morning, then becoming partly cloudy. Waves 1 to 3 ft building to
 2 to 4 ft.

 TUESDAY NIGHT
 North winds 20 to 25 kt. Slight chance of
 showers and thunderstorms in the evening. Waves 4 to 6 ft
 occasionally to 8 ft building to 5 to 8 ft occasionally to 10 ft.
 A small craft advisory will likely be needed.

 WEDNESDAY
 North winds 15 to 25 kt. Mostly sunny. Waves 5 to
 8 ft occasionally to 10 ft subsiding to 4 to 7 ft occasionally to
 9 ft. A small craft advisory will likely be needed.
 
 $$