The dates of Diwali change every year, though the five day festival generally falls between late October and early November. The Hindu calendar is based on both the sun and moon (while the Gregorian calendar is only based on the sun). In India, the holiday always falls on the 15th of Kartik, the first month of the Hindu lunar calendar corresponding with the first new moon of the lunar New Year. In 2021, Diwali begins on November 4; in 2022, Diwali begins on October 24; and in 2023, Diwali begins on November 12.