out of a clear blue sky

Idioms  

1. Also, out of the blue. Without warning, suddenly, as in Her offer to help us with the fundraising came out of a clear blue sky, or We got a check from Aunt Ruby out of the blue. These metaphoric terms allude to something dropping unexpectedly from the sky. [Late 1800s] Also see out of nowhere.

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Example Sentences

Devastation struck out of a clear blue sky for Yana Stepanenko.

From Seattle Times • May 18, 2022

The first FRBs struck astrophysicists like thunderbolts out of a clear blue sky; no theory had predicted their existence.

From Scientific American • Oct. 13, 2021

The winds can rise to catastrophe out of a clear blue sky.

From The New Yorker • Dec. 1, 2014

The second came quite literally out of a clear blue sky, appearing without warning and then disintegrating about 30 seconds later over Chelyabinsk.

From Economist • Feb. 21, 2013

The sun shone into Anya’s face out of a clear blue sky.

From Anya and the Nightingale by Sofiya Pasternack