|The Blue Moment|
From the beginning of December to mid-January is “Kaamos” in Finnish, which is the word to describe the Polar Night.
As you no doubt know, above the Arctic Circle in winter there are very few hours of daylight. However, it's a misconception that these areas endure 24 hours of darkness in the winter. Although at the winter solstice the Poles themselves might experience this, most places above the Arctic Circle (and below the Antarctic Circle) experience various forms of 'Polar Twilight'.
Here's how Wikipedia explains it:
Polar twilight occurs in areas that are located at the inner border of the polar circles, where the sun will be on or below the horizon all day on the winter solstice. There is then no true daylight at the solar culmination, only civil twilight. This means that the sun is below the horizon, but by less than 6°. During civil twilight, there may still be enough light for normal outdoor activities because of light scattering by the upper atmosphere and refraction. Street lamps may remain on and a person looking at a window from within a brightly lit room may see their reflection even at noon, as the level of outdoor illuminance will be below that of many illuminated indoor spaces.
Less scientific perhaps, though more eatherally beautiful, is the so-called 'Blue Moment' - a point where the sun rises to a certain height above the horizon and drapes the snowy landscape in shades of blue --