Another resource is wikitravel.
Of particular interest:
Great question! I'll see you there. I did a google search on the weather, because I had the same questions. Found that the averages aren't too much different from what I experience here in Ohio. Probably don't need leggings.
I'll probably just wear boots and warm socks, jeans. I always wear an undershirt under my clothes, so 2 layers of tshirts and a jacket or hoodie.
https://weatherspark.com/averages/28846/2/Bergen-Hordaland-Norway
Hey, also from Portugal going this august, I ordered this one from Amazon https://www.amazon.es/-/pt/dp/B09FF9M782/ref=sr_1_213?crid=W6KTNYKPK6XQ&keywords=diamond%2Bcandy%2Bwomen%2Bwinter%2Bski%2Bjacket&qid=1654778541&sprefix=diamond%2Bcandy%2Bwomens%2Bwinter%2Bski%2Bjacket%2Caps%2C125&sr=8-213&th=1&... , it had really great review and the price is very good, it arrived and it’s really warm and waterproof so far, as I tried putting tap water on it 😂 but I guess the real proof will be in Bergen
As far as the basic Norwegian vocabulary is concerned, you could easily begin learning on your own some common Norwegian words and phrases from scratch with flashcard apps like the Beginner Norwegian.