Hanukkah will start on Christmas Day in 2024 in rare cases

This year, the first night of the Jewish holiday Hanukkah falls on the same day as Christmas for the first time since 2005.

Christmas and Hanukkah both always fall on the 25th, but in two different months, with Christmas coming on December 25th in the Gregorian calendar and Hanukkah starting on the 25th of the month of Kislev in the Jewish calendar.

Hanukkah’s start date on the Gregorian calendar varies from year to year because the Jewish calendar is based on lunar-solar calendar cycles. According to Chabad, months under the Hebrew calendar follow a lunar cycle lasting about 354 days. Not to fall behind the approximately 365-day solar calendar, there is a 13th month on the Jewish calendar every few years to make a “leap year”.

Another difference is that on the Jewish calendar, holidays begin at sunset and continue until the next day, so Hanukkah, which lasts eight days, will begin this year hours after the start of Christmas.

The holiday, also known as the “Festival of Lights,” celebrating the rededication of the temple in Jerusalem in the 2nd century BC after the Jews overcame the rule of the Greeks. While rededicating the temple, they found a small amount of ritually pure oil, enough for just one day, and used it to light the menorah, a multi-branched candelabra. That oil miraculously lasted eight days.

This year’s celebration continues through January 2, 2025.

The first day of Hanukkah and Christmas have coincided only a handful of times since 1900, according to the Jewish Federations of North America. The holiday started on the same day in 1910, 1921, 1959 and 2005. Rabbi Joshua Stanton, vice president of interfaith initiatives for Jewish Federations of North America, sees it as an opportunity for learning, collaboration and unity.

“The goal is not to proselytize; it’s to learn deeply from each other,” Stanton told CBS News in a statement. “It is others who see you as you see yourself.”

Rabbi Moshe Hauer, executive vice president of the Orthodox Union, said he sees the convergence of holidays as an opportunity to appreciate the diverse religious landscape of the United States

“This is something we’ve learned that we must work hard to protect, especially in times of rising anti-Semitism and other forms of hatred,” Hauer told CBS News in an email.

The convergence of holidays also presents unique opportunities and challenges for interfaith families. Some people celebrate what is known as “Chrismukkah”, a name derived from the overlapping of holidays made popular by the TV series “The OC”

“I think that especially as Hanukkah has come to be seen as a kind of Jewish Christmas, we are seeing more and more interest in how they can correspond to each other. Both holidays are interested in light and in the presence of God in dark times,” Candida Moss, professor of theology at the University of Birmingham, told CBS News. “And this, of course, provides a huge opportunity for interfaith families to celebrate both traditions side by side.”

Rabbi Rick Jacobs, the president of the Union for Reform Judaism, said he believes each holiday should be given its due, rather than being mixed together, “because I think that hurts the uniqueness of each one.”

“But proximity can actually lead us to understand more, to appreciate more about those who make up different faiths, and for us to create more light in what is often a very dark time of year,” Jacobs told CBS News.

The two holidays coincide again in 2035 and 2054, according to Hebcal.

It is also rare that Hanukkah starts on Christmas Eve. It has happened twice in the last 50 years: in 1978 and 2016.