Too early to be thinking of summer, you say? Tell that to Crypton Future Media who has just announced a bunch of summer- and swimsuit-themed merchandise for their VOCALOID characters, coming on June 7!
All merchandise is based on the character illustrations by さかなへん / Sakanahen.
A4 Clear File Folder: ￥350
Acrylic Keychain: ￥650 JPY each
Clear Water Bottle: ￥1,500 JPY
Each item is scheduled for release for animate, ACOS, Gamers, and other stores all across Japan on June 7. They can also be pre-ordered right now on MOVIC: https://www.movic.jp/shop/r/r102615
Source: Hatsune Miku Official Blog