Hanami (花見, literally "flower viewing") is the Japanese traditional custom of enjoying the beauty of flowers, especially cherry blossoms (桜 or 櫻 sakura). The practice of hanami is more than a thousand years old, and is still very popular in Japan today. It takes place in the spring, contrary to the custom of Momijigari (紅葉狩り), which is celebrated in the autumn. The blossoms only last for a week or two, usually from March to April, and they are followed by the media and waited for by most of the Japanese people. Full bloom (満開 mankai) usually comes about one week after the opening of the first blossoms (開花 kaika). Another week later, the blooming peak is over and the blossoms are falling from the trees.
A more ancient form of hanami also exists in Japan, which is enjoying the plum blossoms (梅 ume) instead. This kind of hanami is popular among older people, because they are more calm than the sakura parties, which usually involve younger people and can sometimes be very crowded and noisy.
It is important to note that the Japanese call this not only "hanami", but also ohanami (お花見), adding an "o" in front, literally meaning "to view the flower blossoms".