English meaning of the festival
Vaikasi is the second month in the Tamil calendar. Visakam is the name of the Nakshatra (star) that is reckoning at that time.
How the date is decided annually
Vaikasi Visakam occurs on the full moon day in the month of Vaikasi.
Significance of the festival to Hinduism
It is believed that Visakam is one of the names of Lord Muruga. Vaikasi Visakam is dedicated to Lord Muruga as it is believed to be the birthday of Lord Muruga. Lord Muruga is believed to bestow success, victory, good fortune, and good health. According to the Skanda Purana, anyone chanting the mantra of Lord Muruga will be blessed with all kinds of spiritual powers, especially knowledge and courage.
How to observe/practice
Temples arrange Yagya (hawan), Abhishekam, and deity worship. Devotees are encouraged to offer milk for the Abhishekam. Sweet Prasadh is offered to the Temple deity. Famous hymns dedicated to Lord Muruga are recited.