

Jamieson Cox of Time magazine felt that the song "doesn't have much lyrical meat on its bones, but coming on the heels of one of the most severe winters in recent memory, listeners are likely hungry for anything that suggests a warmer, sunnier season. Lewis Corner of Digital Spy rated "Summer" three-and-a-half out of five stars, calling it "a bright and vibrant banger destined to soundtrack the warmer months". The song received mixed to positive reviews. Harris's vocal range spans from G 2 to D 4.


It follows the chord progression C–Em–D–Am–G/B–C. "Summer" is composed in the key of G major and has a tempo of 128 beats per minute. On 11 March 2014, Harris posted fifteen-second clips of the song on Instagram up until 14 March, when it was released digitally in certain territories and made its radio debut on Capital FM.
