Weather Control Device (環境維持装置 Kankyō Iji Sōchi, Environment Maintenance Device) is a device that controls the weather, utilizing seithr to operate. It is implied that every Hierarchical City has one.
In chapter 7 of BlazBlue: Remix Heart, the incomplete Regulation Grimoire caused the Ars Magus of the 15th Hierarchical City of Torifune's weather control device to go haywire, so the city was covered in snow.
Due to the destruction of the Cauldron in Snow Town of Akitsu-Kō by Ragna the Bloodedge, their device can no longer control the weather properly, causing large amounts of snow to pile up. This device also affects weather in its sister city, Akitsu-Otsu, but Otsu has a desert instead of snow.