In July of the summer calendar, the "fire" star went down the mountain, and the work of cutting cold clothes in September was handed over to women. In January, strong winds collide with objects, and in February, it is freezing. How can I finish this year without clothes? Repair tools in March and step on the fields in April. Take my wife and children to the farmland to deliver meals. Tian Tian was very happy to see the farmers working in the fields.
It means that the weather turns cold in July of the lunar calendar, and just after dark, you can see the big Mars falling from the west. The first sentence is an introduction, and the weather is getting cold. It's time to sew cold clothes If you want to observe today, you have to wait until August and September in the solar calendar.
Another article, Zuo Zhao's Three Years in Office, says: "In the fire, the cold and heat recede", that is to say, when the big Mars (Antares) appears in the south in the morning, the cold and the heat recede when the big Mars appears in the south at night.
This explanation can be found in Zheng Xuan's Biography of Mao Poetry in Han Dynasty and Kong's Justice of Mao Poetry in Tang Dynasty. According to this, some contemporary people translate "fire starts in July and clothes are given in September" into "Mars is full in July and women make cold clothes in September".