midnight sun 
noun
The sun when seen at midnight during the summer in either the Arctic or Antarctic Circle.The glow over Stockholm these days isn't just the midnight sun hanging above the arctic circle....
- It's more famous as the summer land of the midnight sun, but in winter, Lapland is the land of the midday dark.
- One-seventh of Sweden lies within the Arctic Circle, the ‘land of the midnight sun,’ where the sun never really sets for three months during the summer.