Đêm tháng năm chưa nằm đã sáng, ngày tháng mười chưa cười đã tối
Direct English translation
On the night of the fifth month, before lying down it is already dawn; on the day of the tenth month, before smiling it is already dark.
Giải thích tiếng Việt
English explanation
This proverb expresses folk experience about seasonal daylight: around the fifth lunar month, days are long and nights are short, while around the tenth lunar month, days are short and nights are long. It is used when referring to seasonal change, farming time, and the yearly rhythm of daily life.