In old Hindu legends, Chaitra and Baisakha months are described as Madhu Mass. Lord Jagannath is worshiped as Madhusudan in these two month.
In these month, devotee who is sighting the Madhusudan on boat ( Chapa ) with full respect and devotion, get more virtue. In summer days, people are in most painful situation, they all want to cool down body temperature through bath and doing water sports. Just like humans Lord of Puri ( Jagannath ) need exactly the same feeling of enjoyment these days of Summer. Representative deity of Lord Jagananth Sri Jagannath, Rama Krishna, Lakshmi, Saraswati and five Shivas, in special palanquins move to the Narendra Pond for a sacramental evening sail every day for 21 days. Some special rituals like bath on Chandan Tob, wearing flower ornaments and swim in placed on grandly decorated boats for an evening cruise of the tank are observed. Other details you can follow Chandan Jatra
