What month is the annual tide watching day?

Every year on the eighteenth day of the eighth month of the lunar calendar.

Introduction:

Tide Watching Day refers to the tide watching on the Qiantang River, on the 15th day of the 8th month of the lunar calendar every year, the tide of the Qiantang River is the largest, and the tide can reach several meters. Tide watching began in the Han Wei Dynasty (the first century to the sixth century AD), flourished in the Tang and Song dynasties (the seventh century to the thirteenth century AD), after more than 2,000 years, has become a local custom.

Anciently, the best place to watch the tide in Hangzhou was around Phoenix Hill and Jianggan. Due to the change of geographical location, from the Ming Dynasty onwards, Haining Yanguan is the first resort for tide-watching, so it is also called "Haining tide-watching". On the day of the tide, especially on the eighteenth day of the eighth month of the lunar calendar, the road like a stream of cars, people like a tidal wave.

Extended information

Related background:

Qianjiang River tide cause in addition to the moon, sun gravity, but also with the mouth of the Qiantang River like a trumpet shape. Qiantang Jiangnan Jiangnan Ochishan east of nearly 500,000 acres of land reclamation like a peninsula like blocking the mouth of the river, so that the Qiantang River Ochishan to the outside of the twelve section of the work is like a bottle with a big mouth, the tide is easy to enter the difficult to retreat.

Hangzhou Bay outside the mouth of up to 100 kilometers wide, to the outside of the twelve work section is only a few kilometers wide, the riverbed of the eastern section of the river mouth and the sudden rise of the beach is high and shallow, when a large number of tides from the mouth of the Qiantang River when the tide came in, due to the rapid narrowing of the river, so that the tide could not evenly rise, it had to push the front wave, the front wave is not fast enough to run, the back of the wave caught up with the layer after layer of stacked up.

The Tang and Song dynasties, when the court in the Qiantang River to review the sailors, tide and tide show are concentrated in the lunar calendar August 18 (rumored to be the tide God's birthday), after the custom, it became a traditional festival.

Baidu Encyclopedia - Tide Watching