once in a blue moon

IPA(Pronunciation)

idiomatic not-comparable

(idiomatic) Very rarely; very infrequently.

Japanese Meaning

非常に稀に起こる / めったにない / ごく稀に

I visit my hometown once in a blue moon, usually only for special family events.

私は故郷にはごくまれにしか帰らず、たいてい特別な家族の行事のときだけです。

Sense（1）

(idiomatic) Very rarely; very infrequently.