The Double Ninth Festival (Chong Yang Festival in China, Hong Kong, Macao and Taiwan, observed on the ninth day of the ninth month in the Chinese lunar calendar, is a traditional Chinese holiday, mentioned in writings since before the Eastern Han period (before AD 25.) This year it falls on October 4.
According to the I Ching, nine is a yang number; the ninth day of the ninth lunar month (or double nine) is hence also called "Double Yang” Festival (重陽節). It is customary to climb a high mountain, drink chrysanthemum liquor, and wear the zhuyu (茱萸) plant, Cornus officinalis. (Both chrysanthemum and zhuyu are considered to have cleansing qualities and are used on other occasions to air out houses and cure illnesses.)
On this holiday some Chinese also visit the graves of their ancestors to pay their respects.
On December 28, 2012, the Standing Committee of the Eleventh National People's Congress revised and passed the Law on the Protection of the Rights and Interests of the Elderly, which came into effect on July 1, 2013, and stipulates that "the ninth day of the ninth lunar month is the Old Age Day". The Double Ninth Festival in 2013 became the first statutory festival for the elderly in China. The establishment of the Festival for the Elderly is conducive to promoting the virtues of the Chinese people to respect, care for and help the elderly.
華人耳熟能詳的唐朝詩人王维著名詩作《九月九日憶山東兄弟》：「獨在異鄉為異客，每逢佳節倍思親。遥知兄弟登高處，遍插茱萸少一人。」描畫了九九登高的人情風貌。2022年的九九重陽，落在陽曆十月四日星期二。
重陽節是華人文化中的傳統節日，相信是依據《易經》六陰九陽之說。民間在該日有登高的風俗，所以重陽節又稱「登高節」。「九九」諧音「久久」，有長久之意，有祈求長壽和祭祖、敬老崇孝之傳統，故又稱敬老節或老年節。2012年12月28日第十一屆全國人民代表大會常務委員會修訂通過、自2013年7月1日起實施的《老年人權益保障法》規定，“每年農曆九月初九為老年節”。2013年的重陽節成為中國第一個法定的老年節。設立老年節，有利於弘揚中華民族敬老、養老、助老的美德。
重陽節與除夕、清明、盂蘭三節也是中國傳統節日裡祭祖的四大節日。“六”定为陰数，“九”定为陽数，九月九日，日月並陽，两九相重，故曰重陽，也叫重九。重陽節或敬老節較常見的民間活動包括-祭拜祖先、敬老活動、登高健行、踏青、佩茱萸、賞菊。