I'm not so much a summer person. But in january you start to wonder what the sun looks like... because you hardly ever see her. It's just grey grey grey. If you have a full-time job I think the darkness gets to you more. Especially if you work in a place with no windows. Then you would go to work when it's dark and come home in the dark. Like an owl. Hoot hoot.
When I lived in Lofoten the winters were even darker than here. In january we had what they called the bluehour. For an hour or two during the day... it went from dark to darkblue... like in a cloudy twilight. That was the lightest it would get. For a photographer, this was rather frustrating. So many of us spent those days in the dark room.
However, once spring comes to Lofoten it just gets lighter and lighter until the sun never sets. I worked at a restaurant in Lofoten during the summer. If I ended my shift at 01.30 A.M I would still be walking home with the sun on my face. That was really nice!