Bathing in the river on July 7 is mainly to prevent prickly heat. In Guangdong, Fujian, Guangxi, Hainan and other places, there was another high temperature after July 7, which was called autumn tiger. The bite of autumn tiger is not comparable to ordinary heat energy. People who don't get prickly heat in summer may have it all over their faces in winter, and July 7th is the protagonist of this custom.

Not only Hakkas, but also many places in Guangdong, Guangxi and Fujian have the habit of storing water and swimming in the river on July 7, so they don't pray for peace and wealth, and they don't get prickly heat. In Guangdong and Guangxi, some areas are not friendly to women, but under this custom, married women can also swim happily in the river on July 7.

However, this custom did not last long. History should be three or four hundred years, based on the legend of the Cowherd and the Weaver Girl. When I was a child, the story of the Cowherd and the Weaver Girl heard by Hakkas was not a love story, but a story of a fairy descending to take a bath. People who usually restrict their children from swimming in the river are relieved because there are many people in the river that day. Therefore, in these places, children are sometimes happier on the seventh day of July than on the New Year, because after all, everyone has gifts for the New Year, and they can play with water aboveboard on the seventh day of July.

The custom of the seventh day of July is actually very simple. Most Hakka festivals are for entertainment and health preservation, and there are few wishes, because people here believe that man can conquer nature, and their initial intention for July 7 is to keep their bodies from itching and their children from making trouble. Children with prickly heat can't sleep well in their hometown. If it doesn't last long, children can grow up healthily. This is the origin of the custom of "On July 7th, immortals washed PP in the river".