Cold Yanks

Canadian people. Often used in the UK, possibly not used elsewhere, since Yank is mainly used by the British to refer to Americans. Cold Yanks being a joke about how hard it can be to tell the difference sometimes with American accents and Canadian ones, though Canada is much colder. It's not usually meant in a bad vibe way, more as a somewhat dismissive term of endearment.

"I thought from the accent they were surely Yanks, but they turned out to be Cold Yanks"
"What?"
"Cold Yanks. You know, Canadians".