Shani Peyarachi in Tamil Astrology is the transition of Shani Navgraha from one rashi to another and is very important in astrology and for personal horoscope. Shani Peyarachi date and time is December 21. In 2011, Shani transits from Kaniya Rashi (Virgo) to Tula Rashi (Libra) at 07.51 AM on Wednesday, December 21st (Indian Standard Time).
Lord Shani will remain there for next two and half years. This movement of Saturn or Shani from one ‘rasi’ or zodiac to another occurs once in two and a half years.
This transition is of great importance at the Saneeswara Temple in Thirunallur. Those Rashi people that will have bad influence in their horoscope due to this transition arrive to offer prayers at the temple on the particular date.
You can read more about Shani Peyarachi in this article.