Chaar Din ki Chandni Meaning

Chaar din ki Chandni, literally moonlight of four days, is a common Hindi phrase which means good times don't last too long.

Though, here in the phrase there is no mention of negative part and it only says the moonlight (good days) would stay (only) for four days(limited period). The longer version of the phrase makes a complete proverb that says 'Chaar din ki chandni phir andheri raat' literally meaning 'the moonlight is here for four days and then dark nights will be there again), implying the same thing.