Read the following examples to guess the meaning for out of the blue
I was washing dishes after dinner last night when out of the blue, my roommate from college called me on the phone! I hadn't spoken to her in over 5 years so I was really surprised that she called.
Julia and Oscar were dating for more than 8 months. They went out for a nice dinner last Saturday night. Right before dessert, Julia suddenly broke up with him. There was no explanation and no warning. It was totally out of the blue. Oscar was so sad and shocked.
out of the blue is a common expression that signals when something unexpected happens without warning.
In the first example, the speaker and her college roommate have not had contact for a long time, so the phone call was really surprising and unexpected. She called out of the blue.
In the second example, Oscar had no idea that Julia was going to end the relationship. He thought he was just going to have a nice date with his girlfriend! When she broke up with him before dessert, of course Oscar was shocked! It was totally out of the blue!
This idiom is from LSI's book "Speaking Savvy," which is used in the level 5 Listening/Speaking class. For more information, please visit http://www.languagesystems.com