Sashti, or Shasti, is the sixth day after Amavasi (new moon) and Purnima (full moon) in a traditional Hindu calendar. The Sashti after Amavasi is considered highly auspicious by Muruga devotees. The Sashti that falls in Aipasi month (October – November) is known as Skanda Sashti and a six day Kanda Sashti Vrat is observed during period. In November 2008, the date of Sashti is November 4th. It must be noted here that in some calendars the Skanda Sashti festival is also marked on November 3. Please check with your local temple or local calendar.
The Skanda Sashti Vrat begins after the new moon day (Amavasi) in Aipasi month. The Amavasi day was on October 28 and the Skanda Sashti Vrat began on October 29. The six-day Vrat period should have ended on November 3, which also should have been the Sashti day. Pratipada, Dwitiya, Tritiya, Chaturti, Panchami and Shasti are the normal count of days. But occasional in the Hindu calendars days overlap thus there are two Dwitiya in some calendars.