Off the coast of Labrador, the Atlantic Marine Ecozone essentially begins at the edge of the continental shelf and travels east out to sea. But east and south off Newfoundland lie the relative shallows of the Grand Banks, the trailing edge of the great North American tectonic plate. Average water depths outside the shelf can reach down thousands of metres, with depths on the Grand Banks of less than 150 metres over broad areas. Tidal ranges within the ecozone are normally one to two metres, but the Bay of Fundy is the exception, with its famous tidal bores topping 15 metres.
The ecozone is generally temperate due to the influence of the massive Gulf Stream. Prevailing winds blowing off the land from the west and southwest also moderate the ocean climate. In August, surface water temperatures can vary between 10 and 23°C. But like the Northwest Atlantic Ecozone, winter and early spring ice can be plentiful along the east coast of the Avalon Peninsula and in the Cabot Strait between Newfoundland and Nova Scotia. Icebergs are a common sight in late winter and spring off the Newfoundland coast and on the Grand Banks. The mainland coast of Nova Scotia and the Bay of Fundy (except for its northernmost reaches) are essentially ice-free. Off Newfoundland, mixing of the warm currents from the south and the Labrador Current from the north produces some of the most famously dense fog banks on the planet.