Why Does Hanukkah Change Dates Every Year?

While Christmas is celebrated every December 25, year in and year out, the date for Hanukkah is a moving target. Here's why.

Hanukkah is an eight-day Jewish holiday that is observed in late fall or early winter. Hanukkah celebrates the victory of a band of Jewish warriors over their oppressors. It also commemorates the miracle God performed when a vial of oil—needed to rededicate the Holy Temple in Jerusalem—lasted for eight nights instead of one. The word “Hanukkah” is Hebrew for “dedication.” That’s just one of 18 Hanukkah facts you probably never knew. Figuring out when Hanukkah starts is likely another since the holiday changes dates every year.

Why does Hanukkah change dates every year?

Most American and Christian holidays are celebrated according to a 365-day Gregorian (or solar) calendar. The observance of Jewish holidays, however, follows a lunisolar calendar—one that keeps track of the earth’s orbit around the sun to determine a year’s length but also factors in the phases of the moon to determine the beginning and end of each new month.

The dates on these two calendars don’t neatly match up, so Hanukkah appears to change dates every year. On the Hebrew calendar, though, it always begins on the 25th of Kislev, the same as the date of the very first Hanukkah celebration.

What are the differences between a lunar and solar calendar?

A lunar month is shorter than a solar one, at 29.5 days, so 12 lunar months only add up to about 354 days. “The rabbis who ultimately set the calendar knew if [they used] a truly lunar calendar, the holidays would march backward by eleven days every year. If you have a holiday that celebrates the harvest in October, you can’t have it coming in June,” says Rabbi Norman Patz, rabbi emeritus of Temple Sholom of West Essex, in Cedar Grove, New Jersey, and visiting rabbi of Temple Beth Shalom in San Juan, Puerto Rico. “It had to be reconciled with the solar calendar,” which is how we ended up with a lunisolar one.

In addition, rather than adding a leap day every four years like the Gregorian calendar, the Jewish or Hebrew calendar adds an entire leap month to seven out every 19 years, using a complicated formula. Because of this, a year in the Hebrew calendar can range from 353 to 385 days.

How long is Hanukkah?

Like all Jewish holidays, Hanukkah starts in the evening. It is observed for eight consecutive nights, as we recall the miracle that occurred when the oil in the Temple lasted for eight days instead of one. Though the dates of the holiday may change on the solar calendar, the length of the holiday never does.

When does Hanukkah start?

Because of the varying lengths of the lunisolar calendar, Hanukkah sometimes falls around the American holiday of Thanksgiving. In 2013, Hanukkah and Thanksgiving coincided, creating a freaky once-in-a-lifetime double holiday, “Thanksgivukkah,” for American Jews. Hanukkah can begin as early as November 28 and as late as December 27, depending on the year.

Usually, though, Hanukkah starts sometime in December. Because of this fact, and the modern tradition of giving gifts at Hanukkah, many people have come to believe that Hanukkah is a sort of “Jewish Christmas,” but nothing could be further from the truth. Hanukkah actually began nearly 600 years before the first Christmas celebration.

In 2020, Hanukkah begins on the evening of December 10, with the last night falling on December 18.

Why does Hanukkah always start in the evening?

In the story of creation as told in the book of Genesis, the description of each day concludes with the phrase, “And there was evening and there was morning,” leading rabbis to determine that a day begins with evening. Therefore, holidays, like all other days in the Hebrew calendar, commence in the evening.

If you do want to give a Hanukkah gift, consider our picks.

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Laurie Budgar
Laurie Budgar is a certified speech-language pathologist (MS, CCC/SLP) who spent over a decade helping people with brain trauma, stroke, MS and Alzheimer’s regain language, speech, swallowing and cognitive skills. She contributes regularly to RD.com, where she writes about health, pets and travel. Previously, she was the editor at Momentum, the magazine of the National Multiple Sclerosis Society. Under her direction, the magazine won its first-ever Folio awards for best complete issue and best article. She has covered health, nutrition and lifestyle topics for Healthline, Parenting, LIVESTRONG.com, Delicious Living, Natural Solutions and more. She has written about travel destinations and profiled small businesses for AAA Colorado, American Way, the University of Denver and Fortune Small Business.