Karthika Somavaram Vratham (Mondays in Karthik Month) are highly auspicious as per Telugu panchangam and Kannada calendar. In 2018, Karthika Somavaram vratham dates are: November 12, November 19, November 26 and December 3.
There is Koti Somavaram in 2018 – November 14. In some areas, any day of Saptami which coincides with Shravana Nakshatra, before Kartik Purnima is also considered highly auspicious as Koti Somavaram and sometimes also referred to as Koti Somavaram.
In some parts of Gujarat and Maharashtra also, Karthika Somvar Vrata is observed with utmost gusto.
As per the North Indian calendars and beliefs, Kartik Month is dedicated to Lord Vishnu and Goddess Lakshmi. Lakshmi Puja and Vishnu puja are observed throughout the month in some communities in North India. But, according to South Indian beliefs Kartik Month is dedicated to Lord Shiva also and the Mondays in this month considered highly auspicious.
Telugu and Kannada people celebrate Karthika Somavara Vratam by visiting Shiva temples, performing punya snana in holy rivers such as Godavari, Krishna, Tungabhadra, Cauvery.
In North India, the similar puja and vratha are observed on Shravan Somvar days (Mondays in Shravan Month).