In China, when people write or speak, they frequently make use of such idioms such as “the cold falls on the third nine-day period in winter” or “the coldest days of the year in the nine-day periods”. In China, the winter is measured in nine-day periods because the winter is divided into nine-times-nine. After struggling with windy snow and coldness for thousands of years, the Chinese working people created the folk songs to describe the wintry weather.

Here is a very interesting version:

During the 1st and 2nd nines,
People greet each other without holding out their hands.
The 3rd nine hears the wind blowing the fences
(just like the sound produced by an ancient bamboo pipe with a reed month).
During the 4th nine, sleeping in bed at night is like camping outdoors.
The 5th nine sees the poor dancing in the streets.
Stop dancing, as spring chill is waiting ahead
(The poor fidget to get warm for they wear thin clothes.)
The 6th nine sees flies in the houses
(It’s less chilly.)
During the 7th nine, people wrap cotton-padded gowns around their neck
(Instead of putting them on, it’s getting warm).
The 8th nine sees the cats and dogs lying on cold ground.
The 9th nine witness the end of the suffering of the poor,
Who are just about to stretch and sleep when mosquitoes and fleas come out.