out of a/the clear (blue) sky
Completely unexpectedly; out of nowhere. She seemed so surprised by the news that it must have come out of a clear blue sky. You need to work hard—opportunities don't just come out of the clear blue sky.
out of the clear blue sky
Unexpectedly. She seemed so surprised by the news that it must have come out of the clear blue sky. You need to work hard—opportunities don't just appear out of the clear blue sky.