White Nights

light nights occurring during the period when sunset approaches sunrise and legal twilight extends all night. The white nights are most marked near the time of the summer solstice in the northern and southern hemispheres of the earth, in localities north of 59.5° N lat. and south of 59.5° S lat. respectively. The duration of the white nights depends on the geographic latitude of the place. For example, the period of white nights extends from June 11 through July 2 in Leningrad, from May 27 through July 17 in Petrozavodsk, and from May 13 through July 30 in Arkhangel’sk. The definition of white nights is arbitrary; light nights, during which the sun drops a little more than 7° below the horizon, can still be considered white. Very light nights also occur in localities outside the boundaries indicated above.