Marine Forecast
Illustrated map of Grand Traverse Bay

Marine forecast

Lake Michigan from Whitehall to Pentwater, MI

current wind
6 kt W
Gusts
10 kt
Seas
2.6 ft
Period
5 sec
Air
62°F

Observed Tue 2:54 PM | LMZ870

Gusts now
10 kt
Seas now
2.6 ft · 5 sec
Air
62°F
72-hr peak
40 kt
Peak seas
16 ft

In brief

At 2:54 pm EDT on Oct 13, 2026, NDBC station LDTM4 (Ludington, MI, 25 miles away) measured wind from the W at 6 kt, gusting to 10 kt; buoy 45210 measured seas of 2.6 ft. The NWS forecast for Lake Michigan from Whitehall to Pentwater, MI issued at 10:07 am EDT on Oct 13, 2026 reads, for rest of today: “West winds 10 to 20 kt becoming northwest 10 to 15 kt. Waves 4 to 7 ft occasionally to 9 ft subsiding to 2 to 4 ft.”

Source: National Weather Service Milwaukee/Sullivan WI forecast; NDBC observations

Wind forecast · ktPeak 40 kt

05101520253035404550Wed 14Thu 15Fri 1605101520253035404550Wed 14Thu 15Fri 16
Sustained GustOct 13-16 | EDT

Seas forecast · ftPeak 16 ft

012345678910111213141516Wed 14Thu 15Fri 16012345678910111213141516Wed 14Thu 15Fri 16
Oct 13-16 | EDT

NWS marine forecast

PeriodForecast
Rest Of TodayWest winds 10 to 20 kt becoming northwest 10 to 15 kt. Waves 4 to 7 ft occasionally to 9 ft subsiding to 2 to 4 ft.
TonightNorth winds 5 to 10 kt becoming northeast. Chance of showers and slight chance of thunderstorms. Waves 1 to 3 ft subsiding to 1 to 2 ft.
WednesdayNortheast winds 10 to 15 kt becoming north 10 to 20 kt. Waves 1 to 3 ft building to 4 to 6 ft occasionally to 8 ft.
Wednesday NightNortheast winds 10 to 20 kt becoming east. Waves 4 to 6 ft occasionally to 8 ft.
ThursdayEast winds 10 to 20 kt. Chance of showers in the morning, then showers likely in the afternoon. Waves 4 to 6 ft occasionally to 8 ft.
Thursday NightNortheast winds 10 to 15 kt backing to northwest gales to 35 kt. Showers likely. Waves 2 to 4 ft building to 7 to 10 ft occasionally to 13 ft.
FridayNorthwest gales to 45 kt. Chance of showers. Waves 18 to 23 ft occasionally to 30 ft.
SaturdayNorthwest winds 10 to 20 kt becoming southwest 15 to 25 kt. Waves 6 to 9 ft occasionally to 12 ft subsiding to 3 to 5 ft.

Issued Tue 10:07 AM by Milwaukee/Sullivan WI (product GLFLM).

Synopsis

West to northwest winds are expected today, remaining breezy as low pressure departs east. Light north winds expected tonight night, with isolated thunderstorms possible across far southern portions of the lake. Northerly winds continue Wednesday as high pressure moves eastward over the northern half of the lake, then easterly into Wednesday night as high pressure moves eastward. Winds weaken into Thursday as low pressure moves east through the Mississippi Valley, then become northwesterly gales late Thursday night into Friday as low pressure moves into the eastern Great Lakes and intensifies. A few storm force gusts are possible Friday. LMZ261-362-364-366-563-565-567-868-132130- Lake Michigan from Seul Choix Point to Rock Island Passage 5 NM offshore to Mid Lake- Lake Michigan South of a line from Seul Choix Point to the Mackinac Bridge and north of a line from Charlevoix MI to South Fox Island 5 NM offshore- Lake Michigan from Charlevoix to Point Betsie MI 5 NM offshore to Mid Lake- Lake Michigan from Point Betsie to Manistee MI 5 NM offshore to Mid Lake- Lake Michigan from Rock Island Passage to Sturgeon Bay WI- Lake Michigan from Sturgeon Bay to Two Rivers WI 5 NM offshore to Mid Lake- Lake Michigan from Two Rivers to Sheboygan WI 5 NM offshore to Mid Lake- Lake Michigan from Pentwater to Manistee MI 5 NM offshore to Mid Lake- 907 AM CDT Tue Oct 13 2026 SHEBOYGAN WI TO PENTWATER MI NORTH...

TimeWindGustSeasWater
Tue 2:54 PM 6 kt W 10 kt — —
Tue 1:54 PM 7 kt W 12 kt — —
Tue 12:54 PM 7 kt W 13 kt — —
Tue 11:54 AM 6 kt W 12 kt — —
Tue 10:54 AM 6 kt WNW 12 kt — —
Tue 9:54 AM 6 kt W 11 kt — —
Tue 8:54 AM 6 kt W 9 kt — —
Tue 7:54 AM 11 kt SSW 15 kt — —
Tue 6:54 AM 8 kt SSW 15 kt — —
Tue 5:54 AM 13 kt SSW 18 kt — —
Tue 4:54 AM 12 kt SSW 18 kt — —
Tue 3:54 AM 12 kt SSW 17 kt — —

Observed Tue 2:54 PM at NDBC buoy LDTM4 (Ludington, MI), 25.4 miles away. Seas from buoy 45210 (Rawley Point East, WI (269)), 37.4 miles away, at Tue 2:56 PM.

What is the marine forecast for Lake Michigan from Whitehall to Pentwater today?

Rest Of Today: West winds 10 to 20 kt becoming northwest 10 to 15 kt. Waves 4 to 7 ft occasionally to 9 ft subsiding to 2 to 4 ft.

Is there a small craft advisory for Lake Michigan from Whitehall to Pentwater?

No advisories, warnings or watches are in effect for NWS zone LMZ870 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 Lake Michigan from Whitehall to Pentwater right now?

Seas are running 2.6 ft at a 5-second period, measured at NDBC buoy LDTM4 Tue 2:54 PM, 25.4 miles from this zone. The forecast peaks at 16.0 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 LMZ870, issued by Milwaukee/Sullivan WI, 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 GLFLM, issued Tue 10:07 AM. Observations: NOAA National Data Buoy Center station LDTM4, read Tue 2:54 PM. Retrieved Oct 13, 3:42 PM. Conditions offshore change faster than any page can be rebuilt, so check the current NWS bulletin and your own instruments before going out.