Meaning: This idiom can be used in two situations: MEANING 1 To have impractical ideas or dreams. Sometimes the person doesn’t know the facts or reality of the situation. Example: A: I’m going to start learning how to play the guitar. I’m sure it will only take me a couple of months to learn. B: You definitely have your head in the clouds! You’re going to need much longer than two months!
MEANING 2 To be daydreaming and not paying attention to what is happening around you right now. This idiom is often used when the other person is not paying attention. Example: A: What do you think of the new book by Jack Johansen? B: …. (silence) A: Hey! Are you paying attention? Your head was in the clouds, wasn’t it? B: Sorry, I was thinking about what I’m going to have for lunch.