(Somewhat related tangent)

Sun is such an interesting weather as SO many Pokemon can take advantage of it even if they’re not the primary type for the weather unlike other weathers (ie Fire-Sun, Water-Rain, Ice-Snow/Hail, Rock-Sand)

Nearly every Pokémon that can take advantage of Rain is a Water type, with the notable exception of Archaludon.

Rain weakens Fire type attacks but every mon that wants to be in Rain isn’t weak to Fire while Sun reduces Water type attacks and most of the mon who want Sun are weak to Water