ytän

Yötön is a Finnish adjective meaning without night or nightless. It is formed from the noun yö (night) plus the suffix -tön, which in Finnish grammar yields predicates describing the absence of the base noun. In everyday language, yötön is most often encountered in the compound yötön yö, literally a night without night, used to describe periods when night does not fall.

The most well-known use of the term is in reference to polar daylight. A yötön yö refers to a night during which the sun remains above the horizon, a phenomenon that occurs during the Arctic and sub-Arctic summers in regions such as Lapland and other northern areas. The length of the yötön yö varies by latitude and season, with some locations experiencing continuous daylight for several weeks to months around the summer solstice. The concept is closely associated with the broader phenomenon of the Midnight Sun and is a common topic in geography, meteorology, travel writing, and cultural descriptions of northern regions.

In Finnish culture and media, yötön yö can be used descriptively to convey extended daylight, heightened activity, or a sense of continuous brightness. The term is distinct from kaamos, which describes the polar night when the sun does not rise. While yötön emphasizes the absence of night, kaamos emphasizes the absence of daytime.

See also: Midnight Sun, Polar day, Kaamos. Note that in texts using plain ASCII, yötön may be written without diacritics as yoton.