There are at least three artists called September: 1.) A Swedish dance singer. a.k.a. Petra Marklund
2.) A progressive jazz / rock band from ex-Yugoslavia.
3.) An emo band from the 90's from California.
4.) A Doom/Death Metal band from Sweden
1.) Petra Linnea Paula Marklund better known as September (born in Stockholm, Sweden on 12 September 1984) is a Swedish dance singer. Her mother is Slovenian and has a musical past and her Swedish father is a professor in space physics. She started recording music in studios at the age of 12.

Read more about September on Last.fm.