Somvati Amavasya is observed when No Moon falls on Monday (Somvar). In January 2012, Amavasya is on Monday hence it is also considered as Somvati. Somvati Amavasya in January 2012 date is January 23. On 22 January, Amavas begins at 2.20 pm and ends on at 1.10 pm on January 23 as per Indian Standard Time and standard Hindu Panchangam.
January 2012 Amavasya is Magh Amavasya (Mauni Amavasya) as per North Indian Hindi calendars and Poush Amavasya as per Marathi, Gujarati, Telugu, and Kannada calendars.