Stellaris: Cosmic Storms is a mechanical expansion for the grand strategy game Stellaris. It introduces eight new storm types to the galaxy, including Electric Storms and the Nexus Storm, which present both dangers and opportunities for player empires. The expansion includes the "Storm Chasers" Origin, three new Civics such as Astrometeorology and Storm Devotion, and a Weather Forecast Map Mode for strategic planning. Additional content comprises new technologies, resolutions, and edicts aimed at enhancing strategic gameplay.