Vrindavan Parikrama is 12 km approx. journey performed by devotees while walking or by Dandavat Pranam (obeisance) every day. There are few special days having great importance to perform parikrama such as Akshay Navami, Kartik – Krishna Paksha Ekadashi and Shukla Paksha Ekadashi and *Falgun Shukla Paksha Ekadashi.
And after every two years as per Hindu calendar the year is of 13 months. As per Panchang during Adhik Maas parikrama is performed by devotees. 2013 Adhik Maas was in the month of May.
*This year Falgun Shukla Paksha Ekadashi was on 12th of March, 2014 and I did Vrindavan parikrama in two hours thirty minutes.
(Above knowledge shared by Ramkrishna – student of adhyatma)