Rainer is a distinctive boys' name in United States, ranking #4354 in 2012 with 23 recorded births. The name reached its all-time peak in 2018 with 53 births ranking #2464. Since 1996, the popularity has increased by 53.3%. In 2012, approximately 1 in every 82,462 boys born was named Rainer. FALLING Recent data shows the name is currently falling.