>>20930453It hasn't been confirmed what the actual affects of the new abilities are yet, but allow me to entertain you with some good guess.
The most common theory is that they will make perma-rain and perma-sun, much how drizzle and drought functioned in gen 3-5.
Im hoping that they are actually MORE powerful forms of the weather. While still lasting only 5 turns, they would boost their respective elements power even more, but only for the primal poke itself.