Amavasya is new moon day in Hindu calendar. It is significant day as many rituals are performed only on Amavasya Tithi. Amavasya falling on weekday Monday is known as Somvati Amavasya and Amavasya falling on weekday Saturday is known as Shani Amavasya.
All Amavasya days are appropriate to perform Shraddha rituals to appease ancestors. Amavasya day is also appropriate day to perform Kalasarpa Dosha puja.
20 January (Tuesday) Magha Amavasya
18 February (Wednesday) Phalguna Amavasya
20 March (Friday) Chaitra Amavasya
18 April (Saturday) Vaishakha Amavasya
18 May (Monday) Jyeshtha Amavasya
16 June (Tuesday) Ashadha Amavasya
16 July (Thursday) Ashadha Amavasya
14 August (Friday) Shravana Amavasya
13 September (Sunday) Bhadrapada Amavasya
12 October (Monday) Ashwin Amavasya
11 November (Wednesday) Kartik Amavasya
11 December (Friday) Margashirsha Amavasya