I never got as far north as Tromsų, but a former teaching colleague spent a year there and said that there was a big town party when the sun finally came back above the horizon.

I was in Trondheim and environs visiting relatives in July, and it never really got dark, only dusky. The sun was on the horizon at about 11:30, briefly dipped below, and came back up about 3:00AM, but there was always some light in the sky.