IU has gifted fans with an unexpected release, saying farewell to the lingering summer heat with a heartfelt ballad.

A Sudden Morning Release

On September 10 at 7 a.m., IU released her digital single Bye, Summer without any prior promotion or teaser. The track blends her lyrical vocals with a refreshing band sound, evoking the cool breeze at the end of summer.

A lyric video accompanied the release, portraying a boy and girl sharing memories in the summer sun before parting ways at the close of the season.

Born from Her World Tour

Bye, Summer was originally created during IU's first world tour HEREH last year. She performed it for the first time at the Seoul encore concert in September 2024.

Back then, IU introduced the song with heartfelt words: "This summer was the best because I spent it with you. It felt longer than usual, filled with love, and I wanted to capture that in a song." She performed it while playing guitar herself, and in a memorable moment, rain that had been falling stopped as the song ended—creating a scene fans still recall as magical.

The live clip later trended on YouTube, sparking continuous requests from fans for an official release.

Expanding Her Stage

Alongside her music, IU continues to balance acting projects. She will hold a fan meetup titled Bye, Summer on September 13–14 at KSPO Dome in Seoul. She is also filming the MBC drama The 21st Century Crown Princess.