It is true that you don't have to travel far north to get a sense of life without night since even Stockholm does not get too dark at night during summer.
However, we recommend you to check out Abisko, situated approximately 100 km west of Kiruna, one of the most northern points of Sweden. This land of the midnight sun will strike you with its beauty and natural greatness. Since it is so far north, you will also probably not see the night at all, thus, be prepared for some minor sleeping problems. If you enjoy some less solitary places and want to party all night in the daylight, pop into Stockholm with its multitude of street bars and clubs which await summer with great anticipation!