Songfacts®:

• Danielle Haim is the romantic partner of producer Ariel Rechtshaid, who was diagnosed with cancer while she and her sisters were making Something To Tell You. This sunny, horn-laden song was inspired by that difficult time. (According to Danielle, he's in the clear now.)
• Danielle explained the story of the song: "We were touring on and off at this time and every time we were on the phone with each other or when I would come home in between shows, I wanted to be this light that shined on him when he was feeling very dark. I wanted to be his hope when he was feeling hopeless."
  
  In her attempts to lift up her partner, Danielle kept singing over a bass line:
  
  I'm your sunny girl
  I'm your fuzzy girl
  I'm your summer girl
  
  The phrase "summer girl" stuck with her, and a year or two later Danielle remembered the demo and pulled it up from her phone. She took it to her producer friend Rostam Batmanglij, formerly of Vampire Weekend, to see if he could anything with it. He wrote the sax part within a few minutes of working on the track.
  
  After realizing the "doot doot doot part" of "Summer Girl" reminded them of Lou Reed's "Walk On The Wild Side," Haim and Batmanglij added a bass line as a homage to the classic 1972 tune.
  
  Danielle then played her demo to the original inspiration, Ariel Rechtshaid, who added the finishing touches.
• Lou Reed is credited as a writer on "Summer Girl," along with Rechtshaid, Batmanglij and the Haim sisters.
• A video was released for the song directed by Boogie Nights and There Will Be Blood filmmaker Paul Thomas Anderson. The clip shows the Haim sisters walking through the streets of LA, shedding layers upon layers of clothing until they are summer appropriate. The auteur is a known Haim fan, having previously directed their music videos for "Right Now," "Little Of Your Love" and "Night So Long."
• Fun Fact: Years before Paul Thomas Anderson became Haim's go-to video director, the girls' mother was his art teacher.
• Danielle and Rostam approached U2's Bono to provide vocals on the song's closing line, "And I can see the angels coming down. Like a wave that's crashing on the ground." He was up for it, but had to pull out because of illness.