Celebrated by people of Hindu, Buddhist, Jain, and Sikh beliefs as well as those of Indian and non-Indian descent, Diwali is celebrated over 5 days - from the 13th day of the dark half of the lunar month Ashvina to the second day of the light half of the lunar month Karttika. The corresponding dates in the Gregorian calendar usually fall in late October and early November. The 3rd day of Diwali is the biggest day of the celebration (noted on the wheel).
"There isn’t just one reason to celebrate the five-day holiday. Pankaj Jain, a professor of anthropology, philosophy, and religion at the University of North Texas, says that the ancient celebration is linked to multiple stories in religious texts, and it’s impossible to say which came first, or how long ago Diwali started."  Generally, Diwali is a festival of new beginnings celebrating the triumph of good over evil, light over darkness, and wisdom over ignorance.
The name is derived from the Sanskrit term dipavali, meaning “row of lights.” During the festival, diyas (small earthenware lamps filled with oil) are lit and placed in rows along the parapets of temples and houses and set adrift on rivers and streams. Homes are decorated, and floors inside and out are covered with rangoli, consisting of elaborate designs made of colored powder, rice, sand, or flower petals, to bring good luck. Check out the Hindu American Foundation's Diwali Toolkit to design your own rangoli!