Marine Forecast
Illustrated map of Lake Michigan at Chicago

Marine forecast

Wilmette Harbor to Northerly Island, IL

current wind
6 kt E
Gusts
7 kt
Seas
0.7 ft
Air
70°F
72-hr peak
26 kt

Observed Tue 2:20 PM | LMZ741

Gusts now
7 kt
Seas now
0.7 ft
Air
70°F
72-hr peak
26 kt
Peak seas
5 ft

In brief

At 2:20 pm CDT on Oct 13, 2026, NDBC station CHII2 (Harrison-Dever Crib, Chicago, IL, 5 miles away) measured wind from the E at 6 kt, gusting to 7 kt; buoy 45198 measured seas of 0.7 ft. The NWS forecast for Wilmette Harbor to Northerly Island, IL issued at 9:41 am CDT on Oct 13, 2026 reads, for rest of today: “West winds 10 to 20 kt becoming northeast and diminishing to around 10 kt in the afternoon. Partly cloudy.”

Source: National Weather Service Chicago/Romeoville IL forecast; NDBC observations

Wind forecast · ktPeak 26 kt

05101520253035Wed 14Thu 15Fri 1605101520253035Wed 14Thu 15Fri 16
Sustained GustOct 13-16 | CDT

Seas forecast · ftPeak 5 ft

012345Wed 14Thu 15Fri 16012345Wed 14Thu 15Fri 16
Oct 13-16 | CDT

NWS marine forecast

PeriodForecast
Rest Of TodayWest winds 10 to 20 kt becoming northeast and diminishing to around 10 kt in the afternoon. Partly cloudy. Waves 1 to 2 ft.
TonightNortheast winds around 5 kt. Showers and thunderstorms likely. Waves 1 to 3 ft.
WednesdayNortheast winds 10 to 20 kt. Chance of showers in the morning. Waves 2 to 4 ft building to 3 to 5 ft occasionally to 8 ft late in the afternoon.
Wednesday NightNortheast winds 15 to 20 kt becoming east overnight. Slight chance of rain overnight. Waves 4 to 6 ft occasionally to 8 ft. A small craft advisory will likely be needed.

Issued Tue 9:41 AM by Chicago/Romeoville IL (product NSHLOT).

TimeWindGustSeasWater
Tue 2:20 PM 6 kt E 7 kt — —
Tue 1:50 PM 6 kt ENE 7 kt — —
Tue 12:50 PM 1 kt NE 2 kt — —
Tue 11:50 AM 4 kt W 5 kt — —
Tue 10:50 AM 12 kt W 14 kt — —
Tue 9:50 AM 17 kt W 19 kt — —
Tue 8:50 AM 18 kt W 21 kt — —
Tue 7:50 AM 23 kt W 25 kt — —
Tue 6:50 AM 21 kt WSW 22 kt — —
Tue 5:50 AM 18 kt WSW 20 kt — —
Tue 4:50 AM 18 kt SW 21 kt — —
Tue 3:50 AM 16 kt SW 18 kt — —

Observed Tue 2:20 PM at NDBC buoy CHII2 (Harrison-Dever Crib, Chicago, IL), 5.3 miles away. Seas from buoy 45198 (Chicago Buoy), 7.0 miles away, at Tue 2:10 PM.

What is the marine forecast for Wilmette Harbor to Northerly Island today?

Rest Of Today: West winds 10 to 20 kt becoming northeast and diminishing to around 10 kt in the afternoon. Partly cloudy. Waves 1 to 2 ft.

Is there a small craft advisory for Wilmette Harbor to Northerly Island?

No advisories, warnings or watches are in effect for NWS zone LMZ741 as of the last update on this page. Advisories can be issued at any time; check the current bulletin before leaving the dock.

How high are the waves at Wilmette Harbor to Northerly Island right now?

Seas are running 0.7 ft, measured at NDBC buoy CHII2 Tue 2:20 PM, 5.3 miles from this zone. The forecast peaks at 5.0 ft Fri 2 PM.

What do the wind speeds in knots mean?

One knot is 1.15 mph. The National Weather Service issues a small craft advisory for sustained winds of roughly 22–33 knots or hazardous seas, a gale warning at 34–47 knots, and a storm warning at 48 knots and above. Exact advisory thresholds vary by forecast office and by water body — a bay reaches dangerous chop at a lower wind speed than open ocean.

Where does this forecast come from?

The forecast text is the National Weather Service's own marine bulletin for zone LMZ741, issued by Chicago/Romeoville IL, reproduced in full. The wind and seas charts are drawn from the NWS gridded forecast for a point inside the zone. Observations come from the nearest reporting NDBC buoy. We are not affiliated with NOAA or the National Weather Service.

Forecast: NOAA/NWS product NSHLOT, issued Tue 9:41 AM. Observations: NOAA National Data Buoy Center station CHII2, read Tue 2:20 PM. Retrieved Oct 13, 2:42 PM. Conditions offshore change faster than any page can be rebuilt, so check the current NWS bulletin and your own instruments before going out.