Not to knowledgable with instruments so hope these make sense haha

Feel like Dry would be an electric guitar. Showy, and people like it's one of the main stars of a song.

I imagine Spring would be a violin. Something that people think of when it comes to classical and proper instruments. Also melodic and harmonious.

Rainy would probably be a drum set. Maybe not as popular as other instruments, but still important. Can be steadily be played in the background, or be loud and thunderous.

Autumn would be a fiddle. Playful and down to earth.

Winter I think would be a flute. Playful and energetic.

Summer I think would be a drum. Tries to keep the other instruments in rhythm. But considered a fun instrument.