I think the general consensus here is that winter on the mainland is clean - it gets cold, and stays cold, and you can enjoy winter activities without wading through slush up your ankles every day. At least, that's how my parents describe their winters in northern Manitoba - they emphasize that winter comes and stays far more than the cold. I think most people consider the mainland to be colder, and the prairies especially so. And I also get the impression most people know BC has very mild winters.
There's little quirks that always stand out, though. Most people here, for example, have absolutely no idea that cars can even be plugged in, much less that in colder climates they must be in order to start again.
And here, the most obvious tell is using an umbrella. They never took off here, probably because of our generally windy weather, and at this point they're just foreign to the culture. If I see someone with an umbrella, I can be basically certain they've come from away.
Also, Hunter rubber boots are an admired fashion choice. It's not just something that's tolerated in our often slushy conditions, they actually sell for hundreds of dollars and get lovingly posted to Instagram and the like.