Simple Tides / Guides / Boston Tides

Boston Tide Chart

Boston has one of the largest tidal ranges on the U.S. East Coast — around nine to ten feet — and the harbor transforms twice a day as the tide floods in and drains back out.

The pattern

A classic semidiurnal cycle with a big swing: nine to ten feet is normal, more on spring tides near full and new moons. That much water moving means strong currents in the harbor’s narrows and dramatic exposure of flats and ramps at dead low.

Boating the harbor

Plan around the tide, not just the clock: some ramps and moorings go unusable at low water, and the current through the harbor’s constrictions runs hardest mid-exchange. The Harbor Islands are best explored with the tide in your favor — a falling tide can leave a dinghy high and dry.

Fishing

Striped bass and bluefish prowl the harbor, the islands, and the South Shore from spring through fall, and moving water is the trigger — fish the tide changes around structure and current seams. For the wider region, see our New England tide guide.