[teodorlu]

That depends a lot. I live in Oslo now, and have lived in Trondheim and Finnmark near Kirkenes before.

Never used blackout curtains in Oslo or Trondheim, absolutely needed them in Finnmark. I wouldn't say that blackout curtains are the norm in the Nordic countries, especially not Denmark.

But if you're in a place where there's midnight sun, I suggest getting some.

[Symbiote]

Blackout curtains are easily available in Denmark, and I have some, but I don't think that's common.