Rainer is a distinctive boys' name in United States, ranking #7702 in 1999 with 8 recorded births. The name reached its all-time peak in 2018 with 53 births ranking #2464. Since 1996, the popularity has decreased by 46.7%. In 1999, approximately 1 in every 240,011 boys born was named Rainer. FALLING Recent data shows the name is currently falling.