At five tracks,
24°C is the shortest material in Lee Hi's catalogue. The album explores the dark side of romantic relationships, the loneliness and the longing, the frustrating relationships, and the break-ups. Musically,
24°C combines these mostly darker themes with generally upbeat musical genres. The opening track of the album, "No One" featuring
B.I of iKon, as a
reggaeton-infused dance track with a "groovy" tune full of vibrant percussion, smooth melodies, and quirky synths. It expresses the longing of a lonely person waiting for a lover to arrive with a knock on her door. Lee Hi's collaboration with G.Soul, "No Way", is an "unashamedly laid back track" with a piano and a low bass. "Love Is Over" is "a gospel, soul-infused ballad" with a jazzy swing rhythm. It functions very much as a typical break-up tune, reflecting on the struggle to move on the relationship. "1,2" featuring Choi Hyunsuk of Treasure, is a "short but sweet" track. "20Min" is the only self-written song by Lee on the album. The "guitar-led ballad" details her anger and annoyance with a certain someone over gentle guitar strums and the sound of water-drops. ==Promotion==