 However, unlike the celebration of the new Gregorian calendar year at midnight on 31 December, the Sinhalese traditional New Year begins at a time determined by astrological calculations.Also unlike 31st night celebrations, where old year ends at midnight and new year begins immediately afterwards; the ending of the "old year", and the beginning of the "new year" occur several hours apart from one another (this span of time is usually 12 hours and 48 minutes, which starts when the sun, as a disk, starts to cross the astrological boundary between 'House of Pisces' and 'House of Aries' and ends when the crossing is complete.The halfway point is considered as the dawn of the new year).