Atmokinesis is a natural ability that all merpeople are shown to have. With this elemental power, merpeople can change and manipulate the various aspects of weather in their favor.
In "Battlelines", Rita was shown using this power to create a storm in a jar and was able to control wind, rain, and lightning. Nixie also demonstrated this power when she created the storm in a jar and when she made a storm cloud over Zac.
In "Stormy Seas", Ondina and Sirena have a contest of mermaid powers, and Ondina demonstrates this power when she creates a storm cloud. Sirena then demonstrates this power by making it rain, followed by thunder and lightning.