Dimmu Borgir vocalist Shagrath either doesn’t know the color of snow, or is trying to convey a subtle anti-racist statement in a metaphor. Here’s what he answers in a recent interview:
Chicago Tribune: What is it about Norway that allows so many black metal bands to flourish?
Shagrath: Mainly it’s a way of thinking. It could be environment. We live in a very dark country where we have a lot of snow. It’s a small country but a lot of bands are able to think outside the box, and not be copycats.
Read full interview here.
Correct me if I’m wrong, but if you live in a country with a lot of snow, isn’t the country technically ‘light’? I mean think about it, snow is white, a lot of snow means a lot of white. Where does the ‘dark’ part come in?

Have you ever seen pictures of Norway? It’s dark there all the time. The darkness that Shagrath is referring to is in the atmospheric sense (i.e. gray clouds).
And if it is snowing, what do you think the odds are that there is a clear sky?
So let’s piece it together: Dark country with a lot of snow. The environment makes it kind of gloomy, and the snow means that it’s got to be pretty damn cold there.
It’s very dark there in the winter time because of all the snow, like the previous commentor said. All the clouds that bring the snow block out the sun. It’s overcast a lot. Also, the nights are much longer in the winter, and the days are much longer in the summer, because it is so far north. If you go far north enough it is dark for almost 24 hours around the winter solstice and light for almost 24 hours around the summer solstice.