Rainer is a distinctive boys' name in United States, ranking #5746 in 1998 with 11 recorded births. The name reached its all-time peak in 2018 with 53 births ranking #2464. Since 1996, the popularity has decreased by 26.7%. In 1998, approximately 1 in every 173,756 boys born was named Rainer. FALLING Recent data shows the name is currently falling.