Artic Circle - Midnight Sun

At the summer solstice (June 22) the apparent course of the sun on the Arctic Circle reaches its greatest northern declination (i.e. its greatest angular distance north of the celestial equator), so that at midnight the sun is still in the sky. In a clear sky this midnight sun is an impressive sight, but even when the sun is obscured by mist or clouds its glowing red ball in the night sky is a memorable spectacle.

Polar day

Exactly on the Arctic Circle this phenomenon of the polar day is visible on only one night in the year, but its duration increases steadily towards the north. At the North Pole the polar day should in theory last exactly half a year, but the refraction of the sun's rays in the earth's atmosphere makes it slightly longer than this. Moreover the altitude from which it is observed also affects the length of time during which the midnight sun can be seen, since the published data are calculated for sea level. Thus an observer on a hill can see the midnight sun some distance south of the Arctic Circle.

"Nordic Cap"

The parts of Norway, Sweden and Finland north of the Arctic Circle - the "Land of the Midnight Sun" - are also known in Scandinavia as the "Nordic Cap" (Nordkalotten, Finnish Pohjoiskalotti).