Chu Shu indicates that the hot summer is coming to an end although it is not cool yet.

 

Chu Shu: Limit of Heat
Chu Shu happens on Aug. 23 each year when the sun reaches the celestial longitude of 150 degrees. Chu Shu in Chinese reflects the changing of temperatures. Chu (pronouncing “chŭ” in Chinese) means “stop” and Shu means “summer,” so Chu Shu indicates that the hot summer is coming to an end. However, it is not cool yet during this period, and in fact it can still be very hot on some days, especially in the afternoons.

A poem written by Bai Juyi during the Tang Dynasty (618-907) describes the scenery of Chu Shu. “When Chu Shu comes, the summer clouds in the sky are breaking up just like the summer heat itself. Cool winds are curling upward. The pond is also surrounded by the atmosphere of autumn. All lotuses have turned into seeds due to the arrival of autumn.”

In most parts of China, customs around the Chu Shu period involve worshiping ancestors and welcoming autumn. An event called the “Hungry Ghost Festival” falls on the 14th and 15th days of the seventh lunar month.

Bai Lu: White Dew
Bai Lu happens every year when the sun reaches the celestial longitude of 165 degrees. It more often refers in particular to the day when the sun is exactly at the celestial longitude of 165 degrees. In the Gregorian calendar, it usually begins around Sept. 7 and ends around Sept. 23. When Bai Lu comes, the weather begins to turn cold. Although the days are still hot, temperatures decrease rapidly after sunset. At night, water vapor in the air condenses when it encounters cold temperatures. These water drops adhere to flowers, grass and trees. When the morning comes, sunshine makes them look crystal clear, spotlessly white and breathtakingly beautiful. That is why the period is known as “White Dew.”

Bai Lu is also a time during which people living in the Taihu Lake region offer sacrifices to the ancient Chinese ruler Yu the Great (2200-2100 BC), who was a hero famous for controlling floods. Every year on the day of Bai Lu, people hold pilgrimages to honor him. The scale of the pilgrimages can last a whole week.