Hanukkah starts at sundown Dec. 14, with Dec. 15 as the first full day of the holiday this year.
What's happening: Hanukkah 2025 begins on a different day on the Gregorian calendar than it did last year (and will next year), but it's on the same date annually on the lunisolar Hebrew calendar.
Between the lines: Hanukkah starts on the 25th of Kislev on the Hebrew calendar.
The Hebrew calendar — also called the Jewish calendar — is timed according to the moon, with a "leap" month added seven times in every 19-year cycle.
It works out that Jewish holidays are around the same time every year — like Hanukkah always being in the winter — and there's a full moon on the 15th of the month and a new moon at the start of the month.
Editor's note: Originally published on Nov. 13, 2023, this story and chart were updated for 2025 and subsequently corrected to remove a reference to this year being a leap year.