Nuclear winter

A nuclear winter is a planet-wide alteration of the climate of a world, usually as the result of a nuclear war or other major nuclear event.

Planets that underwent known nuclear winters include:
 * Earth, which had a limited nuclear winter in the 21st century
 * Uxal, from somewhere after 2248 until 2378
 * The Vaadwaur homeworld
 * Talos IV, sometime (significantly) before 2254