From late May to mid-July, the sun never sets in Kiruna. The midnight sun is not simply "it stays light" — it is genuinely strange and disorienting in ways photographs rarely capture. At 2am the light is golden and long-shadowed, identical to early evening or late morning, and the birch trees are in full leaf, and the temperature is reasonable. Darkness never comes, and your body takes several days to adjust.
The practical experience is this: you can hike, fish, or photograph at midnight with no torch needed. The landscape at midnight in late June — low-angle golden light on tundra, lakes perfectly still, mosquitoes everywhere — has a quality unlike any other time or place.
The best viewing spot is from high ground. Luossavaara, the ski hill north of the city, provides a clear horizon to the north where you can watch the sun skirt the skyline without setting. A number of local cafes and restaurants hold midnight sun celebration events in late June around midsummer. The transition from polar night to midnight sun over the course of April and May is also worth witnessing — the light returns quickly after the darkness of winter, and the change in mood across the town is palpable.
Bring an eye mask for sleeping unless you are staying somewhere with proper blackout curtains — most accommodation in Kiruna is equipped, but it is worth confirming when you book.