Guru Gorakhnath Jayanti is the celebration of the birthday of Guru Gorakhnath who was the spiritual leader of Nath community. As per Hindu calendar it is observed on the 13th day during the Shukla Paksha of Magh month that is in January or February month all over India.
There is a myth that Lord Shiva in the form of Adinath taught secrets of divine power of universe to Guru Matsyendranath. Later Guru Matsyendranath taught the same secrets to Gorakhnath. Gorakhnath wrote many religious books and also gave education to the Nath community. He founded yoga and meditation according to mythology.