Nova Scotia lies in the mid-temperate zone and, although the province is almost surrounded by water, the climate is closer to continental rather than maritime. The temperature extremes of the continental climate are moderated by the ocean.

Described on the provincial vehicle-licence plate as Canada's Ocean Playground, the sea is a major influence on Nova Scotia's climate. Nova Scotia's cold winters and warm summers are modified and generally moderated by ocean influences. The province is surrounded by three major bodies of water, the Gulf of Saint Lawrence to the north, the Bay of Fundy to the west, and the Atlantic Ocean to the south and east. While the constant temperature of the Atlantic Ocean moderates the climate of the south and east coasts of Nova Scotia, heavy ice build-up in the Gulf of Saint Lawrence makes winters colder in northern Nova Scotia; the shallowness of the Gulf's waters mean that they warm up more than the Atlantic Ocean in the summer, warming the summers in northern Nova Scotia. Summer officially lasts from the first Sunday in April to the Saturday before the last Sunday in October.

Rainfall changes from 140 centimetres (55 in) in the south to 100 centimetres (40 in) elsewhere. Nova Scotia is also very foggy in places, with Halifax averaging 196 foggy days per year and Yarmouth 191.