Minecraft wiki entry for Command_blocks_and_functions, associated text: Assuming only admins can get to it, a weather machine can be quite useful, players can turn rain on and off at will. One of the more helpful uses of this technique would be to use a combination of villagers (they run inside when it rains) and some form of redstone machinery to create and automatic rain disabler, this would allow you to shut off the rain almost immediately without needing to use the command, or to have an admin present. It can also be used to create, and/or end, a scenario where it is more advantageous to have rain as opposed to sunlight, and vice versa; such as during a forest fire, or when a thunderstorm is spawning monsters.