This may be a bit of a strange question, but I'm traveling to Norway soon and my hair is different shades of purple and pink. In my city in the US this is reasonably common and most of the trendy salons advertise vibrant hair color, etc. In Norway, if we were going to a nicer restaurant, etc would this be seen as too casual or generally looked down on? Or is this common in cities such as Oslo?

Don't worry.

We have seen various hair colours in Norway, though we avoid finer restaurants. To be safe you might want to wear traditional Norweigian clothing;

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They will just think you're American.

Dye it Gray that is the new fashion.

https://www.cosmopolitan.com/uk/beau...et-grey-hairs/
I would not be bothered. Be yourself, fashion wise.
Dye Your Hair Purple & Live Forever
https://www.loreal-paris.co.uk/produ...-colour/violet

It's quite common in Scandinavia and the rest of Europe. Mellow colors, vibrant, streaks, full head. It's fine.

Wear a Viking headdress with horns and you'll be welcome anywhere.

You'll look like many other older European women.

The strange question is that you will be going to nicer restaurants in Norway. When we were in Bergen a coffee shop "lunch" costs us over $300. Take lots of money!

Purple hair is not common in Scandinavia, blonde is what I would call common in these parts. But no one will care what your hair colour is.

There's this shade of "red" that has long been popular...

I know it's kind of a dumb question, I always panic about standing out in a bad way in other countries, but then everyone is just wearing jeans anyway.

If anyone, anywhere casts aspersions or stereotypes you, based on your appearance then that is their problem.

Clealry, different countries have differing views of certain aspects of dress but one of the greatest advances of the last 100 years is the general acceptance of individuality.

Failing that, I agree, they will instantly recognise you as American.

If you are truly worried just strip your hair color before the trip. Go as a blonde or brunette or whatever is closest to your natural color. I do not in anyway believe this is necessary, but when people get worried over little things that could be changed easily... not like you have full body tattoos

Perhaps dye half your hair blonde so you don’t stand out as much.

Don't worry about your hair if you are going to a nicer restaurant in Norway. Worry about your budget!

Restaurants are generally very casual, even the nicer ones would be smart casual. A coffee shop lunch Norwegian style would cost less than USD 20. Just about all restaurants have a main course around USD 25. Travelling in SF a couple of years ago I didn't find it much cheaper unless you go to fast food joints of low quality. It's mainly alcohol prices that are double.

Yes, I would mostly worry about spending too much - it really is an expensive country.