Christmas Eve is not a fixed day of the week, but it usually falls on December 24th. However, due to the irregularity of the Gregorian calendar, Christmas Eve may occasionally fall on a different day of the week, including Sunday. In recent years, Christmas Eve has fallen on a Sunday on the following dates: 2016, 2018, 2024, and 2035. This means that in the past two decades, Christmas Eve has fallen on a Sunday twice, and it will happen again in 2024 and 2035.