Mistä pohjoinen napapiiri alkaa?
There are a number of definitions of what area is contained within the Arctic. The area can be defined as north of the Arctic Circle (66° 33'N), the approximate southern limit of the midnight sun and the polar night. Another definition of the Arctic is the region where the average temperature for the warmest month (July) is below ; the northernmost tree line roughly follows the isotherm at the boundary of this region.
66° 33'N