Hanuman Jayanti is celebrated to commemorate the birth of Hanuman, the Vanara god, widely venerated throughout India. It is celebrated on the 15Th day of the Shukla Paksha, during the month of Chaitra (the Chaitra Pournimaa).
Hanuman Jayanti is an important festival of Hindus. From early morning, devotees flock Hanuman temples to worship him. Hanuman is an ardent devotee of Lord Rama, and is worshipped for his unflinching devotion to the god.
Hanuman is the symbol of strength and energy. Hanuman is said to be able to assume any form at will, wield rocks, move mountains, dart through the air, seize the clouds and rival Garuda in swiftness of flight. He is worshipped in folk tradition as a deity with magical powers and the ability to conquer evil spirits.
The birth of Hanuman :
Vrihaspati had an attendant called Punjikasthala, who was cursed to assume the form of a female monkey -a curse that could only be nullified if she would give birth to an incarnation of Lord Shiva. Reborn as Anjana, she performed intense austerities to please Shiva, who finally granted her the boon that would cure her of the curse.
When Agni, the god of fire, gave Dasharath, the king of Ayodhya, a bowl of sacred dessert to share among his wives so they may have divine children, an eagle snatched a part of the pudding and dropped it where Anjana was meditating, and Pavana, the god of wind delivered the drop to her outstretched hands. After she took the divine dessert, she gave birth to Hanuman. Thus Lord Shiva incarnated as a monkey, and was born as Hanuman to Anjana, by the blessings of Pavana, who thus became Hanuman's godfather.