Rainer is a distinctive boys' name in United States, ranking #5968 in 2010 with 15 recorded births. This places Rainer in the top 42% of ranked US boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2018 with 53 births ranking #2464. In 2010, approximately 1 in every 127,894 boys born was named Rainer. FALLING Recent data shows the name is currently falling.