section_path: Structure/Month
section_name: Month
paragraph_text: Month
  
  The calendar recognises two types of months: synodic month and sidereal month. The Synodic months are used to compose the years while the 27 lunar sidereal days (နက္ခတ်; from Sanskrit nakshatra), alongside the 12 signs of the zodiac, are used for astrological calculations. (The calendar also recognises a solar month called Thuriya Matha, which is defined as 1/12th of a year. But the solar month varies by the type of year such as tropical year, sidereal year, etc.)
  
  The days of the month are counted in two halves, waxing (လဆန်း) and waning (လဆုတ်). The 15th of the waxing (လပြည့်) is the civil full moon day. The civil new moon day (လကွယ်) is the last day of the month (14th or 15th waning). The mean and real (true) New Moons rarely coincide. The mean New Moon often precedes the real New Moon.
  
  As the Synodic lunar month is approximately 29.5 days, the calendar uses alternating months of 29 and 30 days. The 29-day months are called yet-ma-son la (ရက်မစုံလ), and the 30-day months are called yet-son la (ရက်စုံလ). Unlike in other Southeast Asian traditions, the Burmese calendar uses Burmese names for the month names. Although the names sound foreign in origin to modern Burmese ears, all but three are derived from Old Burmese. The three exceptions—Mleta/Myweta (မ္လယ်တာ / မြွယ်တာ), Nanka (နံကာ), Thantu (သန်တူ)—which all fall during the Buddhist Lent, have been replaced by newer Burmese names (Waso, Wagaung, Thadingyut), which used to mean just the Full Moon days of the three months.
  
  In great leap years, the month of Nayon gets an extra intercalary day called yet-lun (ရက်လွန်) or yet-ngin (ရက်ငင်) and has 30 days. In the Arakanese calendar, the month of Tagu gets the extra intercalary day in great leap years.