A regular or normal year has 12 months; a leap year has 13 months. A regular or normal year has 353, 354, or 355 days; a leap year has 383, 384, or 385 days. The months in a Jain calendar are – Kartak, Maagsar, Posh, Maha, Faagan, Chaitra, Vaishakh, Jeth, Ashadh, Shravan, Bhadarvo, Aaso. The average number of days in a month is 30 but the average number of days in a Lunisolar year is 354 and not 360 (12 months in a year) because it takes the Moon about 29.5 days (not 30 days) to complete the circle around the Earth. Hence one Tithi is eliminated in about duration of two months. The Hebrew, Hindu lunar, Buddhist, and Tibetan calendars are all lunisolar, and so were the Japanese calendars until 1873 and the Chinese calendars until 1912. The Islamic calendar is a pure Lunar Calendar because its date (Tithi) indicates the moon phase but its months are not in phase with the time of the solar year or the season. It does not adjust its calendar to coincide with the sun or the season. Hence no extra month is added every three years. The Gregorian calendar (English CE) is a pure Solar Calendar and its date indicates the time of the solar season but not the moon phase. See also Jainism Vardhaman Mahaveerswami Vikram Samvat References Citations Sources Calendar eras Jain philosophical concepts Lunisolar calendars Time in India