In tokyo and kanto region, it gets warmer. And a little snow is left until early or mid april in those areas. Below are some pictures to give you an idea of what to wear during your stay in japan in the spring.
Spring outfit pastel
Spring fashion show
Spring capsule fashion jackson
CHERRY BLOSSOMKenzas Cherry blossom outfit, Spring outfits japan
March is looked on as spring in japan while it has snow in hokkaido and northern japan.