Why we celebrate holi in march or April and Diwali in october and November?

Holi is celebrated in March or April, marking the arrival of spring and the victory of good over evil, particularly through the legend of Prahlad and Holika. It coincides with the full moon in the Hindu month of Phalguna. Diwali, occurring in October or November, celebrates the victory of light over darkness and good over evil, inspired by the return of Lord Rama to Ayodhya after defeating Ravana. It is observed on the new moon night of the Hindu month of Kartika.