Connecticut · New York boating conditions
Long Island Sound marine forecast
A harbor-by-harbor view of the Long Island Sound marine forecast, from the narrower western Sound through the central reaches to the eastern approaches near the Connecticut River and the Race.
The regional picture
One body of water. More than one kind of boat day.
The official Long Island Sound marine forecast is the National Weather Service coastal waters forecast from the New York (Upton) office, which splits the Sound at New Haven and Port Jefferson into an eastern zone (ANZ330) and a western zone (ANZ335). The NWS issues it about four times a day and updates it when conditions change; the harbor briefings below refresh with the latest available forecast and observation data through the day.
Long Island Sound changes character from its narrower western end to the broader central water and the stronger tidal exchange near the Race. A wind that leaves one shoreline tucked in can build a longer fetch toward the opposite shore.
Use these briefings to compare both sides of the Sound and the harbor closest to each end of a trip. Sheltered river and harbor readings add useful local context - they do not stand in for conditions on the open crossing.
Harbor-level briefings
Compare conditions around Long Island Sound
Western Sound
Harbors around the narrower western Sound and its north-shore approaches.
A western Sound harbor with marinas and protected branches close to the New York state line.
Open marine conditions NYMamaroneck HarborA western Long Island Sound harbor with a long marked approach, several yacht clubs, and protected branches near the Mamaroneck waterfront.
Open marine conditions CTBridgeport HarborA western Long Island Sound port with commercial traffic and nearby shelter in Black Rock Harbor.
Open marine conditionsCentral Sound
Opposite-shore briefings where longer fetch can expose meaningful differences across the Sound.
A broad commercial harbor on central Long Island Sound with protected waters behind its breakwaters.
Open marine conditions CTClinton HarborA compact central Long Island Sound harbor with a protected basin, working marinas, and a marked entrance through shoal coastal water.
Open marine conditions NYMount Sinai HarborA protected north-shore Long Island harbor entered through a narrow, shoal-fringed channel with extensive moorings and quiet water inside.
Open marine conditions NYPort Jefferson HarborA broad north-shore Long Island harbor with ferry traffic, a well-defined entrance, protected anchoring areas, and a busy village waterfront.
Open marine conditionsEastern Sound and river approaches
Connecticut River destinations and the eastern gateway toward the Race.
A classic lower Connecticut River stop with protected moorings and access to river towns and coves.
Open marine conditions CTHamburg CoveA deeply sheltered lower Connecticut River cove reached through the Eightmile River, popular for quiet anchoring and protected cruising.
Open marine conditions CTNew London HarborA deep harbor at the Thames River mouth with naval, ferry, and commercial traffic.
Open marine conditionsTide charts
Tide charts around Long Island Sound
- Bridgeport Harbor tide chartCO-OPS 8467150
- Mamaroneck Harbor tide chartCO-OPS 8516945
- New London Harbor tide chartCO-OPS 8461490
Before leaving the dock
Three useful checks for Long Island Sound
- Compare the Connecticut and New York shore briefings when a route crosses the Sound.
- Check wind direction with tide and current timing near the Connecticut River mouth and the eastern approaches.
- Use the official coastal waters forecast and current observations for the open-water part of the route.
What this regional guide can - and cannot - do
These pages make it easier to compare the latest available forecast and observation inputs around Long Island Sound. 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.
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