This year ‘Karkitaka Vavu’ occurs on separate dates in India and Ontario. It falls on July 17th and in Ontario on August 15th.
The ‘Thithhi’ or Nakshatra for ‘Pitru Kriya’ (the ritualistic homage performed for the souls of departed ancestors), is determined based on whether it is in force at least six and a quarter ‘Nazhikas’ (one nazhika is about 24 minutes) before sunset on that day. In case of a birthday, the determination is based on whether the Nakshatra is in force at least six and a quarter ‘Nazhikas’ after sunrise. There is saying in Malayalam which loosely translates to ‘eat after sleep on birthdays’ and ‘feed and then sleep for Pitru Kriya’. This is to show that the duration a nakshatram exists on a day is not the deciding criteria, but how long it is in force before sunset for Pitru Kriya and after sunrise for birthdays.
If a Tithhi or Nakshatram falls twice in a month, the first one is taken for Pitru Kriya and the second for birthdays.
This year the month of Mithuna lasts for 31 days in India and for 32 days in Canada. A detailed explanation would be inordinately long. However, hopefully it would suffice to state that this difference is caused by the fact that when the Solstice occurs before noon, it is taken as the first day of the month.
In India, ‘Vavu’ begins on the 31st day of the month of ‘Mithunam’ and concludes after sunset on the 1st day of the month of ‘Karkitakam’. Therefore, on the first of Karkitakam, ‘Vavu’ exists for at least six Nazhikas (about 2 ½ hours) before sunset. Therefore, the Pitru Kriya should be conducted on that day. However, Vavu occurs on August 15th also. Since the practice is to conduct Pitru Kriya on the first Vavu day, July 17th is the day (ie. 1st day of Karkitakam) on which it is conducted in India.
In Ontario, the vavu starts on Mithunam 32 (Sunday) in the afternoon and concludes on Karkitakam 1st in the afternoon. The Vavu occurs before sunset on Mithunam 32 and not on Karkitakam 1. August 15th (Karkitakam 30th) has 2 ½ hours of Vavu and hence as per the correct practice, Pitru Kriya should be conducted on this day in Ontario.
Thirumeni Divakaran Namboothiri takes you through the process (Audio: Malayalam) of conducting the Karkkitaka Vavu Bali (recorded in 2022).