What they said:)
Norway is cold sometimes, but Stavanger is more wet and windy than freezing cold, I think. Layering is good, and you might need something waterproof for outerwear. Good shoes/boots are necessary, and scarf, gloves and a hat. You will be able to wear a lot of your excisting wardrobe with thights, and I also recommend buying a thin wool t-shirt (short or long sleeves) to wear next to your skin. You can layer whatever you like on top of them, and then you have more possibilities since you can change the outer layer with whatever you already have. Look for the Pierre Robert brand in Rimi, Rema 1000 etc. These are reasonably priced and of good quality. Wash it with Milo:) It eliminates the bulk from thicker sweaters and keeps you warm.
You can wear red, blue, yellow, rust, olive, black etc - it's entirely up to you. MaryK, I love your outfits!