The full moon of the lunar month Phalguna (Phalguna purnima) is celebrated as the end of the Winter season and the beginning of Spring. According to ancient Hindu traditions, it also was the last day of the year and the new year heralding the Vasanta-ritu or Spring, with spring starting from next day. This day is celebrated as the festival of Holi or festival of colours, a festival of merrymaking, announcing the commencement of the spring season.
The name Holi is derived from the name of the Demoness Holika, sister of the demon King Hiranyakaship who won over the kingdom of earth. He was so egoistic that he commanded everybody in his kingdom to worship only him. But to his great disappointment, his son, Prahlad became an ardent devotee of Lord Vishnu and refused to worship his father.
Hiranyakashyap tried several ways to kill his son Prahlad but Lord Vishnu saved him every time. Finally, he asked his sister, Holika to enter a blazing fire with Prahlad in her lap. For, Hiranyakashyap knew that Holika had a boon, whereby, she could enter the fire unscathed.
Treacherously, Holika coaxed young Prahlad to sit in her lap and she herself took her seat in a blazing fire. The legend has it that Holika had to pay the price of her sinister desire by her life. Holika was not aware that the boon worked only when she entered the fire alone.
Prahlad, who kept chanting the name of Lord Vishnu all this while, came out unharmed, as the Lord blessed him for his extreme devotion.
Thus, Holi derives its name from Holika. And, is celebrated as a festival of victory of good over evil.
This year 2011, the Holi moon coincides with the “Super Moon”, wherein the moon, on its elliptical axis comes closest to the earth after 1993.