Song of the summer is the unofficial designation of the song that is dominant both culturally and commercially between the end of May and the beginning of September in a given year. Although the idea of a song of the summer had been around for years, it became a common term in the 1990s. By the early 2000s, achieving the label of "song of the summer" became a competition urged on by media outlets. In the 21st century, the growing fragmentation of musical sources has made it more difficult for a single song to become overwhelmingly pervasive.