"Summer Girl" began as a demo on Danielle Haim's phone, with lyrics born from a deeply personal place. During her partner's cancer diagnosis, Danielle wanted to be a source of hope and light, leading her to sing "I'm your summer girl" over the initial bass line. The song, which features a saxophone part and bass effects that musically reference Lou Reed's "Walk on the Wild Side," is a tender expression of unwavering support and a desire to bring brightness into darkness. It plays like a warm, comforting embrace.