Festivals are both national and local in character. The many local celebrations are varied; national festivals, though fewer, are marked with a spirit of unity and lavishness. The first day of the first month of the Tibetan calendar (February or March of the Gregorian calendar) is marked by New Year celebrations all over Tibet. Monasteries, temples, stupas (outdoor shrines), and home chapels are visited at dawn, and offerings are made before statues and relics of deities and saints. A special fried cookie known as kha-zas is prepared in every home. Either a real or an artificial head of a horned sheep adorns the offerings. A colourful container filled with barley flour and wheat grain and another container of chang are presented to all visitors, who take a pinch of the contents and make an offering to the deities by throwing it in the air.
The New Year celebrations are almost immediately followed by the Smom-lam (“prayer”) festival, which begins three days after the New Year and is celebrated for 15 days. The festival marks the victory of Buddha over his six religious opponents through debates and the performance of miracles. During this festival, special prayers are offered daily. Prayers, fasting, and charitable donations mark sa-ga zla-ba, the celebration of the anniversary of Buddha's birth, enlightenment, and death—three events that all occurred on the 15th day of the fourth month of the Tibetan calendar.
The death of Tsong-kha-pa, founder of the Dge-lugs-pa sect, is celebrated on the 25th day of the 10th month by the burning of butter lamps on the roofs and windowsills of every house. This festival is known as lnga-mchod. The dgu-gtor festival, or festival of the banishment of evil spirits, takes place on the 29th day of the last month of the Tibetan year. At night a bowl of flour soup and a bunch of burning straws are taken into every room of every house, and the evil spirits are called out. Outside, on a distant path, the soup and straws are thrown and left to burn. You can plan your holidays during these festivals as well but it completely depends on the frequently changing rules of Chinese Government about permit policy. Here is the list of festivals in Tibet.
Tibetan New Year (February or March)
Butter Oil Lantern Festival (February or March)
Saga Dawa Festival (May or June)
Gyantse Horse Race Archery Festival (May or June)
Changtang Chachen Horse Race Festival (August)
Shoton Festival (August)
Bathing Festival (September)
Kungbu Traditional Festival (November or December)
Harvest Festival (September)