Nearly all areas north of the Arctic Circle and south of the Antarctic Circle experience around-the-clock darkness for at least one day a year, always in the middle of winter. Further north of the Arctic Circle and south of the Antarctic Circle, the length of time without daylight steadily increases until at the poles themselves, winter is an uninterrupted six month long polar night.

Refraction and mountains

A few places just north of the Arctic Circle and south of the Antarctic Circle escape the polar night, barely. The refraction of the earth’s atmosphere creates an optical illusion, such that the sun seems to be slightly higher in the sky than it actually is.

This optical phenomenon can have the effect of “moving” the sun just above the horizon. It also gives other locations around the world an extra half hour or so of sun every day, at dawn and at dusk.

Higher elevations see the sun slightly ahead of lower elevations: which can make the difference in seeing the sun at all. Much of “east” Antarctica (between the Weddell Sea and the Ross Sea) is mountainous, a geological continuation of the Andes mountains. Coastal areas here escape the polar night which places at the same latitude in “west” Antarctica experience.

Regions

Eight circumpolar countries in the north share pieces of the polar night. Russia has the most land area north of the Arctic Circle, followed by Canada and Greenland. The United States (Alaska) comes next, followed by the three Scandinavian countries of Norway, Sweden, and Finland. Finally, a tiny tip of Iceland experiences polar night.

In the south, nearly all of Antarctica falls within the Antarctic Circle, except for the tip of the Antarctic Peninsula and a few small coastal regions. Despite the multitude of competing Antarctic national claims, no other country can clearly claim territory south of the Antarctic Circle.

Antarctica

Where the glacial icecap meets the deep polar night, temperatures quickly fall far below what most thermometers can possibly record. Mercury freezes at close to -39 degrees Celsius, near where the Fahrenheit and Celsius scales meet. The absolute reliable limit of an ethanol thermometer is -70 C (-94 F), although ethanol does not freeze until the temperature reaches -114 C (-173 F).

The coldest temperature ever recorded in Antarctica was -89.2 C (-128.56 F) - before the windchill was calculated in.

At those temperatures, carbon dioxide itself turns to dry ice. The lack of atmospheric carbon dioxide would be a problem for breathing, were direct breathing even possible at temperatures so cold.

Were it not for the global regulating ability of earth’s atmosphere, temperatures during polar night would plunge even further, down to the depths of space.

But the depths of the polar winter are not dark, not the way that storm-tossed nights are dark. The very coldest nights are far too cold for storms. The blazing stars shine coldly, brilliant in the crystalline night. Far overhead, the auroral streamers dance.

And yet: people live here. At least eleven children have been born here: a living testament to the human spirit.