it's not every day

• it is not every day

it's not every day

1. (followed by a complement) It is not very common (that).

   It's not every day you see a black swan.

• “it is not every day”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “it's not every day that” (US) / “it's not every day that” (UK) in Macmillan English Dictionary.