In The Left Hand of Darkness, the story takes place on the planet Gethen.
Ursula K. Le Guin’s 1969 novel follows Genly Ai, an envoy from Terra who travels to Gethen on behalf of the Ekumen, a loose confederation of human worlds. Gethen is an ice-covered world with severe cold, so it is also commonly called Winter. “Winter” is therefore a nickname or descriptive name, not a different planet.
The setting is central to the novel’s thought experiment. Gethenians are ambisexual: for most of their monthly cycle they are sexually latent, entering kemmer periodically and adopting male or female sexual characteristics. Genly, who is permanently male by Gethenian standards, initially struggles to understand the society and its assumptions.
Much of the plot moves between Karhide and Orgoreyn, the planet’s major political powers. Anarres and Urras belong to another Le Guin novel, The Dispossessed, which is why they can appear as tempting but incorrect options. Gethen’s cold climate, cultures, religions, and gender system all shape the novel’s exploration of identity and communication.