The Polar Night Counter counts down the days to the winter solstice, the shortest day of the year. After the winter solstice, the days gradually lengthen until the darkness of winter disappears. The counter also shows the duration of kaamos, the polar night during which the sun doesn’t show itself above the horizon, in locations where kaamos occurs.
Kaamos only occurs above the Arctic Circle. In Utsjoki on the northern border, it lasts for almost two months. In Sodankylä, (located farther south, close to the Arctic Circle) the polar night lasts for four days.
Although kaamos is the darkest period of the year, it is rarely pitch black. Finnish Lapland is located close enough to the Arctic Cricle that, although the sun stays below the horizon, sunlight still reaches the upper layers of the atmosphere, allowing some ambient light through. Blue twilight is typical for the polar night in the northern Finland. The moon may also light up the sky, and the snow reflects its light. You might also see the multicoloured northern lights dancing across the firmament.
In the southern parts of Finland there is no polar night, but the days are still short. For example, in Helsinki the length of the shortest day of the year is less than six hours.