Koti Somavaram, Koti Somavaram Vratham, is observed on Shravana Nakshatram which comes before Kartik Purnima (Full Moon in Karthika Masam). In 2017, Koti Somavaram date is October 28, Saturday.
If it is Saptami and Saturday, it is even more auspicious.
If anybody does Abhishekam for Shiva and Parvathi on this day they will get eternity. Lighting ghee lamps before Shiva and Parvathi and doing Rudra Abhisheakam 11 times is very auspicious and they will become detached.
If you perform one Somavara Vratham all your sins and problems of past and present will subside. One will get liberation, divine radiance, and good health by doing Abhishekam with Bilva and lotus to Lord Shiva. This is the greatest opportunity to observe silence, fasting on this day and doing Shiva puja.
“Sarvesham chaiva sahasra koti papanaam sankare samupasthitha koti
somavara vrathebhyo Koti somavra vratham pujyathe sodhanam param”
Sins from many lifetimes, all sorrows, all kinds of pains, and problems and fear will disappear if one does Somavara Vratham, attaining Shiva Loka.
In 2016, Koti Somavaram date was November 7, Monday.
In 2012, Koti Somavaram date was November 19, Monday.