The midnight sun is a natural phenomenon occurring in summer months at latitudes north and nearby to the north of the Arctic Circle, and south and nearby to the south of the Antarctic Circle where the sun remains visible at the local midnight. Given fair weather, the sun is visible for a continuous 24 hours, mostly north of the Arctic Circle and south of the Antarctic Circle. The number of days per year with potential midnight sun increases the farther poleward one goes from the equator. Although approximately defined by the polar circles, in practice midnight sun can be seen as much as 90 km beyond the polar circle, because the sun is a disk and not a point, and the exact latitudes of the farthest reaches of midnight sun depend on topography and vary slightly year-to-year.
Where is the Land of the Midnight Sun? The sun shining at midnight in the arctic or Antarctic summer is known as the midnight sun. Norway is popularly called the “Land of the Midnight Sun” because this phenomenon has been more frequently observed in that region by visitors from western Europe and the United States. The description would be equally applicable to other high latitudes above the Arctic Circle, such as northern. Russia, northern Alaska, northern Canada, and Greenland, where in midsummer the sun does not sink below the horizon at any time within the twenty-four hours of the day. Instead of setting as it does in our latitudes, the sun in these regions merely goes around and around above the horizon, being part of the time in the north. In Iceland, for instance, during June and July, daylight is perpetual and a person can read a book by natural light at any time of the night. Within a distance of about four minutes of arc from the North Pole the sun rises and sets but once a year; in other words, the year is composed of one day and one night, each six months ‘in length. The number of sunrises in a year increases from one at the Pole to 365 at a short distance south of the Arctic Circle. Strictly speaking, only the northern part of Norway lies within the domain of the midnight sun. Similar conditions with the seasons reversed exist in the Antarctic. On March 21 the relative positions of the earth and sun are such that the latter illuminates exactly one-half of the surface of the former, and on that date night and day are equal in length in all parts of the world. Three months later, when the earth has completed a fourth of its circuit around the sun, the North Pole is turned toward the sun and the South Pole away from it. Another three months later the days and nights are once more equal in length everywhere on the earth. By December 21, when the earth has completed three-fourths of its circuit around the sun, the South Pole is turned toward the sun and the North Pole away from it. Of course, the land of the midnight sun is also the land of midday night. In the far north and the far south a person can observe the interesting phenomenon of a sunrise and sunset at the same time. This card sent to mr by Sissel depicts the Land of the Midnight sun appropriately.
