The polar night occurs in the whole Arctic Circle to the north of the northern latitude of 66.6 degrees, and the night of the midnight sun in the entire Antarctic Circle to the south of the southern latitude of 66.6 degrees, on the day of Toji.
冬至の日には北緯66.6度以北の北極圏全域で極夜となり、南緯66.6度以南の南極圏全域で白夜となる。