I think it's a song about how even when your life feels like it's full of troubles that drag you down, you can always recall happy summers of your past and feel warmed by the memories. When you're a kid, summer is the free zone, the land of no problems or responsibilities. Recalling that feeling almost makes things in the present feel okay again, because if magic was possible back then, it's possible that magic will happen again someday.
I think it's a song about how even when your life feels like it's full of troubles that drag you down, you can always recall happy summers of your past and feel warmed by the memories. When you're a kid, summer is the free zone, the land of no problems or responsibilities. Recalling that feeling almost makes things in the present feel okay again, because if magic was possible back then, it's possible that magic will happen again someday.