Massachusetts boating conditions
Massachusetts Bay and Cape Ann marine forecast
Compare Boston Harbor, the South Shore, and Cape Ann before a route leaves harbor shelter for the wider bay.
Tonight: Boston Harbor NW 5 kt, seas ≤1 ft. Massachusetts Bay N 5 kt, seas 2 ft. Best day this week: Wed, Nov 11. Wed, Nov 11 is the mildest day. At least one period is still Caution.
Forecast checked Wed, Nov 11, 2026, 8:03 PM EST · National Weather Service coastal waters forecast issued 7:03 PM EST · harbor briefings updated 8:03 PM EST · water temperature unavailable
Right now
Massachusetts Bay and Cape Ann conditions today
Each flag is that harbor's live call. Zone labels use the coastal waters forecast for the rest of today.
- Boston
NWS coastal waters forecast
Massachusetts Bay and Cape Ann forecast by zone
Each period is scored with the same limits as the harbor pages: 15 kt wind, 20 kt gusts, 2.5 ft seas. Thunderstorms or reduced visibility turn a period to Caution.
Inner harbor, including Hingham
No advisorySouth Shore, North Shore, and Cape Ann
No advisoryOfficial NWS text for each zone
Boston Harbor (ANZ230)
Tonight: NW winds around 5 kt, becoming NE after midnight. Waves 1 foot or less.
Thu: E winds 5 to 10 kt, becoming NE 10 to 15 kt in the afternoon. Gusts up to 25 kt. Waves 2 to 3 ft. Showers likely in the afternoon.
Thu Night: NE winds 15 to 20 kt with gusts up to 35 kt. Waves 2 to 3 ft. Rain.
Fri: N winds 20 to 25 kt, diminishing to 15 to 20 kt in the afternoon. Gusts up to 35 kt. Waves around 2 ft, except 3 to 5 ft at the outer harbor entrance. Rain.
Fri Night: N winds 10 to 15 kt with gusts up to 30 kt. Waves around 2 ft, except 3 to 5 ft at the outer harbor entrance. A chance of rain in the evening.
Sat and Sat Night: NW winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft.
Sun through Mon Night: NW winds 10 to 15 kt with gusts up to 20 kt. Waves around 2 ft. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height.
Massachusetts Bay and Ipswich Bay (ANZ251)
Tonight: N winds around 5 kt, becoming NE after midnight. Seas around 2 ft this evening, then 1 foot or less. Wave Detail: NW 1 foot at 3 seconds and NE 1 foot at 8 seconds, becoming W 1 foot at 2 seconds and NE 1 foot at 8 seconds.
Thu: E winds 5 to 10 kt, increasing to 15 to 20 kt in the afternoon. Gusts up to 25 kt. Seas 2 to 3 ft. Wave Detail: NE 3 ft at 4 seconds and SW 1 foot at 2 seconds. A chance of showers in the afternoon.
Thu Night: NE winds 20 to 25 kt with gusts up to 35 kt. Seas 4 to 6 ft. Wave Detail: E 6 ft at 7 seconds and SE 1 foot at 4 seconds. Rain.
Fri: NE winds 25 to 30 kt, becoming N 20 to 25 kt in the afternoon. Gusts up to 40 kt. Seas 5 to 7 ft. Wave Detail: NE 7 ft at 8 seconds and NW 4 ft at 5 seconds. Rain.
Fri Night: N winds 15 to 20 kt with gusts up to 35 kt. Seas 5 to 7 ft. Wave Detail: NE 7 ft at 8 seconds and NW 5 ft at 8 seconds. Rain likely in the evening, then a chance of showers after midnight.
Sat: NW winds 10 to 15 kt with gusts up to 25 kt. Seas 4 to 6 ft. Wave Detail: NE 6 ft at 8 seconds and NW 2 ft at 4 seconds. A chance of rain.
Sat Night: NW winds around 15 kt with gusts up to 20 kt. Seas 3 to 5 ft.
Sun and Sun Night: NW winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 4 ft.
Mon and Mon Night: NW winds 10 to 15 kt, diminishing to 5 to 10 kt. Seas around 2 ft. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height.
Five-day trend
Wind and seas across Massachusetts Bay and Cape Ann
Day and night bars for each zone, in the same wind and seas chart style as a harbor page. A missing bar is a period the forecast did not quantify.
Boston Harbor
Dashed limit on the harbor pages: 15 kt. Bars are the top of the forecast range.
Dashed limit on the harbor pages: 2.5 ft. Bars are the top of the forecast range.
Massachusetts Bay
Dashed limit on the harbor pages: 15 kt. Bars are the top of the forecast range.
Dashed limit on the harbor pages: 2.5 ft. Bars are the top of the forecast range.
Harbor-level briefings
Compare conditions around Massachusetts Bay and Cape Ann
Boston Harbor and the South Shore
Protected inner-harbor water and South Shore departures facing the open bay.
A large island-studded harbor combining commercial channels, protected waters, and an urban waterfront.
5 ktseas 1 ft54°F water
Small Craft Advisory until Fri 7 PM.
A sheltered South Shore harbor reached through Hingham Bay, with islands, moorings, and shallow margins.
5 ktseas 1 ft54°F water
Small Craft Advisory until Fri 7 PM.
A compact South Shore harbor behind breakwaters with a narrow approach and a working waterfront.
4 ktseas 1 ft54°F water
Gale Watch until Fri 7 PM.
North Shore and Cape Ann
North Shore harbors with different shelter and exposure around Cape Ann.
A densely moored North Shore sailing harbor protected by Marblehead Neck and close to Salem Sound.
4 ktseas 1 ft54°F water
Gale Watch until Fri 7 PM.
A deep Cape Ann fishing port with a protected inner harbor and quick access to Massachusetts Bay.
10 ktseas 1 ft54°F water
Gale Watch until Fri 7 PM.
Tide charts
Tide charts around Massachusetts Bay and Cape Ann
- High tide 12:07 AM · 9.06 ft · Low tide 5:58 AM · 1.3 ft · High tide 12:07 PM · 10.18 ft · Low tide 6:34 PM · 0.25 ft—water unavailable
The regional picture
One body of water. More than one kind of boat day.
Massachusetts Bay opens broadly to the east, while Boston Harbor, Hingham, Marblehead, and Gloucester each provide a different amount and direction of shelter. The water outside the harbor can be a separate boat day from the conditions at the dock.
These briefings compare the latest available wind, wave, tide, observation, and advisory inputs from the South Shore through Cape Ann. Start with the departure harbor, then check the open-bay exposure closest to the route.
Before leaving the dock
Three useful checks for Massachusetts Bay and Cape Ann
- Compare a sheltered departure harbor with the more exposed South Shore or Cape Ann briefing closest to the route.
- Read wind direction and wave period with wave height, especially around headlands and harbor entrances.
- Check the official Massachusetts Bay coastal waters forecast and current observations before leaving harbor shelter.
What this regional guide can - and cannot - do
These pages make it easier to compare the latest available forecast and observation inputs around Massachusetts Bay and Cape Ann. They are planning aids, not navigation or safety guarantees. Check the official coastal waters forecast, current observations and notices, local conditions, and your own boat and crew before departure.
See how Boat or Nope builds each call