Why is northern Scandinavia sometimes called the land of the midnight sun?

Answer 1

What happens in the sky in northern Scandinavia during summer?

(and Alaska, Canada, Siberia … )

Answer 2

The north, south axis of rotation of earth is tilted around 23 degrees from straight up from the plane of its yearly rotation around the sun. Therefore at one time of year, around June 22, the North pole is tilted about 23 degrees toward the sun. That time of year you can see the sun at midnight looking over the north pole from any place north of 90 -23 = 67 degrees north of the equator. That is called the summer solstice. The sun at noon that day is over the tropic of Cancer, which is a latitude about 23 degrees north of the equator. Of course this goes on until the sun dips back toward the equator as the summer wears on and as winter comes you pay it back with short days