Rainer is a distinctive boys' name in United States, ranking #4659 in 2002 with 17 recorded births. The name reached its all-time peak in 2018 with 53 births ranking #2464. Since 1996, the popularity has increased by 13.3%. In 2002, approximately 1 in every 114,204 boys born was named Rainer. FALLING Recent data shows the name is currently falling.