十年唔逢一閏 (sap6 nin4 m4 fung4 jat1 jeon6) — not come across a leap year in the last decade in Cantonese
sapˍ₆十ninˎ₄年mˎ₄唔fungˎ₄逢jatˉ¹一jeonˍ₆閏简 十年唔逢一闰
Mandarin Pinyin: shi2 nian2 wu2 feng2 yi1 run4
Meaning of 十年唔逢一閏
nounnot come across a leap year in the last decade
nounonce in a blue moon; chance of a lifetime; very rare occurrence