Costs in Canada are much lower than in the US, perhaps due to the weak position of the Canadian dollar (CN$), which goes for about US 60 cents, making things here seem 40% lower than "back home." Outside the skiing areas, the high season is summer, the low winter, shoulders summer and fall.
Weather
Ninety percent of the population in Canada lives within 100 miles of the border with the USA, where the weather is similar to that of our Pacific Northwest, the northern Midwest and northern New England (which see), respectively from west to east. Beyond that people belt, it's pretty cold, and gets absolutely frigid up toward the northern extremities of the country. (When I visited Campobello, touched by the Gulf Stream and as far south as you can get in Maritime Canada, last August, the seawater temperature had soared to 48°F, as high as it gets in those parts.)
Activities
When you think Canada, you visualize winter skiing and other snow- and ice-related activities, even the fantastic Winter Carnival in Quebec. But summer here is glorious, too, with abundant fishing, wildlife viewing, hiking (often on disused railway beds), biking, camping and mosquito-slapping. You can fly to distant lakes reachable only by float plane for real-life adventure fishing and camping. You can drive the Alaska Highway (most of it is in Canada, not Alaska). Indoors, you can visit the country's many exciting museums, or go outdoors again to experience the gentler way of life up north, in cities as diverse as Vancouver (with its large Chinese population) or Quebec City (where French is the language of choice).