Rainier is a distinctive boys' name in United States, ranking #3362 in 2025 with 35 recorded births. This places Rainier in the top 24% of ranked US boys' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2023 with 41 births ranking #3045. Since 1996, the popularity has increased by 288.9%. In 2025, approximately 1 in every 48,802 boys born was named Rainier. FALLING Recent data shows the name is currently falling.