Matsushita Yuya - 4 Seasons
it's MY's 1st summer song in his discography & it's a great one
I like this so much more than Bird <3
ARASHI - Summer Splash
track #8 in the 2nd disc of their upcoming 9th album Boku no Miteiru Fukei
Hilcrhyme - Shunkashuto
The hip hop rap duo's breakthough hit , I think you can count this as a summer song :O
if not their latest one Loose Leaf is also nice too