Which group released the 1978 hit single "September"?

Which group released the 1978 hit single "September"? Earth, Wind & Fire released it.

The song came out on November 18, 1978, through ARC/Columbia Records. It was written by Maurice White and Allee Willis, with the musical foundation developed by guitarist Al McKay. The track was first issued on the compilation The Best of Earth, Wind & Fire, Vol. 1 rather than on a newly recorded studio album.

"September" blends disco, funk, and R&B, and became one of the group's signature recordings. It reached No. 1 on Billboard's Hot R&B Songs chart, No. 8 on the Hot 100, and No. 3 in the United Kingdom. The famous opening phrase is often misheard, but the lyric says "ba-dee-ya," a deliberately invented vocal sound.

The title refers to a month, yet the song's lyrics never clearly explain a specific event that happened on September 21. That ambiguity is part of its enduring appeal. Earth, Wind & Fire's name is also commonly shortened to EWF, but the full group name is the canonical answer.