Most people assume that it's horrible up here but to give you a "sort of" average idea for the whole country, you are looking at a range between a hot month of 30C and a cold month of -30C if you're only going as north as Ottawa. Winter is three months like anywhere else but it tends to begin in November and end in March (get it? ha-ha)

There are local sub climates like anywhere else of course, so if you're living on the far east coast, or next to the west coast mountains, you'll get worse and better climate, respectively.