24°C is the first EP by South Korean singer and songwriter Lee Hi, released on May 30, 2019, through YG Entertainment. It is Lee's first release since her three-year hiatus following the release of her studio album in 2016. The EP features the lead single "No One" (누구없소). It is Lee Hi's final release under YG Entertainment.

Lee Ha-yi, known by her stage name Lee Hi, is a South Korean singer and songwriter. She first garnered attention as the runner-up of K-pop Star 1. She debuted with single "1, 2, 3, 4" on October 28, 2012, and reached number one with first week sales of 667,549 downloads. Her first full-length album First Love was released in two parts, part 1 on March 7, 2013, and part 2 on March 28, 2013.