In Norse mythology, what is the name of the three-year winter before Ragnarök?

In Norse mythology, Fimbulwinter is the three-year winter before Ragnarök.

The name Fimbulwinter comes from Old Norse and is commonly understood as “Great Winter” or “Mighty Winter.” Völuspá describes a devastating period of cold, with snow coming from every direction and no summer occurring between the winters.

Fimbulwinter is one of the major signs that Ragnarök is approaching. The social order also collapses during this period: sources describe violence, broken kinship bonds, and widespread conflict. It is therefore more than an ordinary severe winter.

Fimbulwinter should not be confused with Ragnarök itself. Ragnarök is the wider sequence of catastrophes and battles involving the gods, giants, and monsters. Fimbulwinter is the prolonged climatic disaster that precedes the final confrontation.