section_path: Abstract
section_name: Abstract
paragraph_text: The Tibetan calendar (Tibetan: ལོ་ཐོ, Wylie: lo-tho), or the Phukpa calendar, known as the Tibetan lunar calendar, is a lunisolar calendar composed of either 12 or 13 lunar months, each beginning and ending with a new moon. A thirteenth month is added every two or three years, so that an average Tibetan year is equal to the solar year. The 15th century Phukpa calendar is the main Tibetan calendar, and the Karma Kagyu's Tsurluk calendar is also in current use. The Tibetan New Year celebration is Losar (Tibetan: ལོ་གསར་, Wylie: lo-gsar), which falls either in the months of February or March in the Gregorian calendar.
  
  During the Tibetan Empire period, the Tibetan calendar was a seasonally based calendar before the Buddha Shakyamuni 's Kalachakra calendar system, a blend of both the Indian zodiac and Chinese zodiac systems, was incorporated. The Tibetan calendar is the basis of the Mongolian calendar, and the first day of Losar also aligns with the third Mongolian (Hor) month in other almanacs.
  
  Every month, certain dates in the Tibetan calendar have special significance for Tibetan Buddhist practices, as do certain months of the Tibetan calendar year when the anniversaries of events from Shakyamuni Buddha 's life correspond, such as Saga Dawa of the Tibetan fourth month.