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.
