Aug 23, 2010 – Monday is the Rigvediya upakarma for this year 2010. There has been come confusions between the upakarma days this year. although Yajurvediya upakarma has been documented in pachangs as Tuesday, but due to several reasons including the tithi, nakshatra and the day of the week combination, the timing on Tuesday morning for changing the thread considered to be in-auspicious and been celebrated on Aug 23rd , monday itself.
However, one needs to check the respective local calendars for accuracy.
vEdamantra 