Navroz is the Parsi new year's day. The day before is Pateti, the last day of the previous year, and the day to close accounts for the year.

The significance of Pateti is that it is the day to dwell on the wrongs or sins one may have committed the previous year, and atoning for them.

While Pateti is generally observed in August, it is not universal among the Parsis. The Parsis follow one of three calendars. It is the Shahenshahi, and most common, calendar, which has Pateti and the new year in August. The other calendars are the Fasli (the old Persian calendar), which has the day in March, and the Kadimi, which celebrates the festival one month before the Shahenshahis.

The word pateti is derived from Pazend patet, meaning 'repentance'. The Zoroastrian tenets are based on the three ideals of good thoughts, good words and good deeds. Anything that is out of accord with this is considered a sin.

It is natural for anyone to have committed a sin in the course of a year, even if only inadvertently. Pateti is the occasion to redeem oneself by offering patet, or the prayer of repentance, and prepare to greet the new year with a clean conscience.

It is also a day of thanksgiving, to be grateful to God not just for the joys of life but also the sorrows.