When right-clicked while on a ⏣ Private Island, the Weather Stick opens a menu to change the island's weather, which can be set to sunny, raining, or thundering. There's a 5-second cooldown between every use, and the weather will eventually change on its own.
If a Weather Node is placed on the island, the weather selected with the Weather Stick will be set in the node, letting it persist until another weather is chosen or the node is removed.
The Weather Stick's cooldown used to be bugged. Its ability description always displayed a cooldown time, but before version 0.19.1, there was no noticeable limit to how quickly a player could open its menu or select weathers.
The Weather Stick used to be able to remotely pick up placed Weather Nodes. Attempting this without a node placed would display the message "That block isn't valid anymore!".