I loved dark sky, I'm using it for my own smart home app, but I should move away from it much earlier, because it just became so inaccurate I can no longer rely on it. I don't know if this is for my region only, or a country (Poland) or whatever, but if a forecast says it will rain for 7 days straight and there is no rain, but the rain falled immediately after forecast stopped showing any rain then it's worthless to use.
I don't know if Weather Kit will provide the same accuracy.
I'm in a process of switching to Open Weather Map right now, I started when apple announced Weather Kit to Dark Sky users via mail. But I will try this Norwegian API as well.