Daylight

According to Suncalc, sunset in May is nearly midnight and sunrise is before 5am. The sun doesn’t dip too far below the horizon so it never gets completely dark. You probably won’t need a torch to walk around at night but I’d recommend bringing a small one so you can see better in the tent, find stuff inside your rucksack, etc.

Unfortunately, the light nights means there’s really no chance of seeing the northern lights.