Kartik snan, also known as Kartika Snanam, is one of the main rituals in Kartik month. Starting from Kartik Sudda Padyami, Karthik Snan is performed throughout the month in various holy river banks and seas in India.
A large number of devotees visit Lord Shiva and Vishnu temples and perform holy dip during Kartika masam. The legends explain that the significance and spiritual importance of Karthika Snanam are described by the Sage Vasista to King Janaka.
When king Janaka asked Vasista to explain the significance or mahima of kartik snana, he saluted to Lord Shiva, Vishnu and Surya and started. During kartik month, Surya Bhagwan enters into Tula rasi (Thula Sankramanam) and stays in for a month. In this period, Ganga mata turns into ‘drava roopa (liquid form) and spreads into all rivers, lakes and water bodies of the world.
Lord Vishnu resides in these water bodies during Kartika masam, hence those who perform ritual bath in water bodies will be blessed with happiness, prosperity and health as well. And who perform samudra snan or nadi snan during Kartika masam will get the results of Aswamedha yagam. After performing Kartik Snan, lighting lamps in temples is recommended ritual.
Kartik Amavasya Snan and Kartik Purnima Snan are most auspicious rituals. On Kartik Poornima day, many devotees in South India visit Lord Shiva temples and perform Deeparadhana. Prabhodini Ekadashi, Ksheerabdhi Dwadasi and Vaikunta Chaturdasi are also cinsidered as auspicious days for Kartik Snan and Deeparadhana. River banks of Krishna and Godavari become full with devotees who perform Karthika snan and Deeparadhana in temples. Some devotees perform Laksha Deeparadhana (lighting one lac lamps) and Koti Deeparadhana (lighting one crore lamps).
Though, 30 days in Kartik month are significant and auspicious for kartik ritual bath, Kartik Mondays (Karthika Somavar) are considered as highly auspicious for the prominent custom of the month.