Maybe the Yo-Kai Watch games? They are RPGs probably inspired by Pokemon, but better in basically every way.

You play as a kid befriending Yo-Kai (creatures taken from japanese folklore), while exploring a pretty cool city. Has a nice soundtrack as well. The story of the first game is kinda meh, but I think it still has that summer vibe.

The second game is a lot better, with an actual story, more stuff to do and more to explore. Definitely the better game, but playing it first might make the first one less enjoyable afterwards.

Both of these games have that childhood summer adventure vibe, even though I myself didn’t spent my childhood befriending Yo-Kai.