Monthly Vinayaka Chaturthi (Masik Vinayak Chaturthi) is the Ganesh Puja festival held monthly once other than Sankashti Ganesha Chaturthi.
The Chaturthi (Fourth lunar day) which comes after Purnima (in Krishna Paksha) is known as Sankashtahara Chaturthi. And the one which comes after Amavasya (in Shukla Paksha) is referred to as Vinayak Chaturthi.
Note – Monthly Vinayak Chaturthi is different from Sankashti Chaturthi.
Even though every Vinayak Chaturthi is observed by fasting and vrata, the one comes in Bhadrapada Month – Ganesha Chaturthi (Vinayaka Chaturthi) is the important one and one among the biggest Hindu festivals in the world.
The list of Monthly Vinayaka Chaturthi 2018-2019 dates
Friday, 22 December 2017 – Vinayak Chaturthi in Poush Month – Auspicious Time for Ganesh Puja – 11.24 AM to 1.09 PM
Sunday, 21 January 2018 – Vinayak Chaturthi in Magha Month – Auspicious Time for Ganesh Puja – 11.34 AM to 1.26 PM
Monday, 19 February 2018 – Vinayak Chaturthi in Falguna Month – Auspicious Time for Ganesh Puja – 11.34 AM to 1.30 PM
Wednesday, 21 March 2018 – Vinayak Chaturthi in Chaitra Month – Auspicious Time for Ganesh Puja – 11.23 AM to 1.33 PM
Thursday, 19 April 2018 – Vinayak Chaturthi in Vaishakha Month
Friday, 18 May 2018 – Vinayak Chaturthi in Adhik Jyeshta Month
Sunday, 17 June 2018 – Vinayak Chaturthi in Nija Jyeshta Month Month
Monday, 16 July 2018 – Vinayak Chaturthi in Ashada Month
Tuesday, 14 August 2018 – Vinayak Chaturthi in Shravan Month
Thursday, 13 September 2018 – Ganesh Chaturthi – Vinayak Chaturthi in Bhadra Month
Friday, 12 October 2018 – Vinayak Chaturthi in Ashwin Month
Sunday, 11 November 2018 – Vinayak Chaturthi in Kartik Month
Tuesday, 11 December 2018 – Vinayak Chaturthi in Margashirsha Month
Thursday, 10 January 2019 – Vinayak Chaturthi in Poush Month
Friday, 8 February 2019 – Vinayak Chaturthi in Magh Month
Sunday, 10 march 2019 – Vinayak Chaturthi in Phalgun Month