Diwali is the Hindu festival of lights celebrated every year in autumn in the northern hemisphere.Its celebration includes millions of lights shining on housetops, outside doors and windows, around temples and other buildings in the communities and countries where it is observed.The festival preparations and rituals typically extend over a five-day period, but the main festival night of Diwali coincides with the darkest, new moon night of the Hindu Lunisolar month Kartika in Bikram Sambat calendar. In the Gregorian calendar, Diwali night falls between mid-October and mid-November.