Đêm tháng năm chưa nằm đã dậy, ngày tháng mười chưa cười đã tối
Direct English translation
On the night of the fifth month, before lying down one already has to get up; on the day of the tenth month, before smiling it is already dark.
Giải thích tiếng Việt
English explanation
This expresses folk experience about seasonal day and night length: in the fifth lunar month the night is so short that one has barely gone to bed before getting up, while in the tenth lunar month the day is so short that it is dark before one has even finished laughing. This variant emphasizes human daily routine more directly than simply describing daylight.