Janmashtami 2020 will be celebrated on two dates in Mathura, the birth place of Lord Krishna.
While Janmashtami in Dwarkadheesh Temple will be celebrated on August 12. In temples of Vrindavan, Nandgaon and Goverdhan, also will be celebrated on August 12.
Priests attribute different religious practices as the reason for difference in the date of celebration.
Since on the night of August 11, ‘Ashtami of Bhadrapad’ will be in full bloom, the ‘abhishek’ (bathing ceremony) will be done at midnight in Dwarkadheesh Temple. Since ‘Udaya Tithi’ is considered most auspicious, Janmashtami in most of the temples of Brijbhumi, especially Keshav Dev and Bhagwat Bhavan temples of Sri Krishna Janmsathan area, is celebrated on this day.
Though Janmashtami in Radha Raman, Radha Damodar and Tedhe Khambewala temples in Vrindavan will be celebrated on August 12, it will be done during daytime. Since in these temples, worshipping the child form of Lord Krishna is common and waking a child at midnight is inconvenient for him, Janmashtami is celebrated on 11th-12th.
Since Janmashtami in Dwarkadheesh Temple, the main temple of Ballabhakul sect, will be celebrated on August 12, the festival will be celebrated in Gokul as Nandotsava the following day (August 13).
Check this video for detailed Janmashtami Puja Procedure with Mantras and fully explained Puja steps..