Why Do the Dates of Jewish Holidays Change Every Year?

As the Jewish community prepares to welcome the year 5786, you may find yourself double-checking your calendar and asking a familiar question:

“Wait, wasn’t Rosh Hashanah in September last year?”

The short answer? It was. And it will be again… just not on the exact same Gregorian date.

At Hillside Memorial Park and Mortuary, we understand how sacred time is in Jewish life. It guides how we remember, how we mourn, and how we celebrate. As we approach the High Holy Days, we wanted to share a brief explanation of why Jewish holidays “move” each year and why, in reality, they don’t.

The Jewish Calendar: Same Same but Different

The key to understanding the shifting dates is remembering that the Jewish calendar is a lunar calendar. That is, it’s based on the cycles of the moon, not the sun. While the Gregorian calendar used in everyday life is solar (365 days, give or take a leap year), the Jewish calendar counts months that begin with each new moon, making them about 29 or 30 days long.

Twelve lunar months add up to about 354 days: 11 days shorter than the solar year. That difference might not seem like much, but over time, it would throw the holidays completely out of sync with the seasons. Passover, which must fall in spring, would slowly migrate through winter, fall, and summer.

To solve this, Jewish tradition adds a leap month: a second month of Adar seven times every 19 years. This complex system keeps the calendar aligned with both the moon and the seasons, ensuring holidays stay rooted in their traditional contexts.

A favorite joke captures the spirit of this calendar confusion:

"When is Chanukah this year?"
"Same as always—the 25th of Kislev!"

Indeed, Jewish holidays always fall on the same date on the Jewish calendar, but since that calendar shifts in relation to the Gregorian one, holidays appear to “move” from year to year.

Sacred Mathematics and Ancient Intent

Today, we rely on calendars, algorithms, and smartphone reminders to track these changes. But in ancient times, the Sanhedrin would declare the start of a new month after reliable witnesses observed the new moon. It was a communal, spiritual, and even judicial act to mark time in accordance with sacred rhythm.

Later, in the 4th century CE, Hillel II introduced a mathematically fixed calendar system that we still follow today. This calendar even accounts for practical concerns—such as ensuring Yom Kippur doesn’t fall too close to Shabbat, or that Hoshanah Rabbah doesn’t land on a Saturday, which would interfere with its observance.

One Calendar, Many “New Years”

Interestingly, while Nissan is considered the first month of the Jewish calendar (because Passover commemorates the beginning of Jewish freedom), the New Year itself—Rosh Hashanah—falls in Tishri, the seventh month. This mirrors the way many secular calendars work: the fiscal year might start in July, the academic year in August or September, and the Gregorian year in January.

So as we look forward to the High Holy Days and the start of 5786 this Tishri, it’s worth remembering that the Jewish calendar doesn’t drift—it dances. It reflects a deep reverence for both cosmic cycles and practical life, just as our traditions ask us to honor the past while embracing renewal.

At Hillside Memorial Park and Mortuary, we are proud to uphold these sacred traditions and rhythms as we support our community through every season of life.

Shana Tova. May the year 5786 bring you sweetness, peace, and meaning.

As we enter this new year, we are pleased to provide you with a complimentary Jewish calendar for 5786. Hillside’s calendar will help you observe Jewish holidays, follow the weekly parshah, keep track of candle lighting times, and honor other important traditions throughout the year. To request yours, fill out the form on our website here: https://www.hillsidememorial.org/calendar-request

< Older Post

Newer Post >

Marking Time, Holding Hope: Hillside’s 5786 Calendar

August 19, 2025

As the Jewish year of 5786 approaches, Hillside Memorial Park and Mortuary is honored to share our new annual calendar—created to help our community observe Jewish holidays, weekly parshiyot , candle lighting times, and other moments of meaning. This year’s calendar is built around a theme that feels especially poignant: Hatikvah —“The Hope.” The title of Israel’s national anthem, Hatikvah carries a resonance that has only deepened in the wake of the ongoing tragedies in Israel. It is more than a song; it is a promise and a prayer, echoing through our traditions and reminding us that hope is not passive. It is an active, sustaining force that binds us together, even in times of uncertainty. As we turn its pages, the calendar invites us to move through time with intention—not only marking days and seasons, but honoring the moments that give Jewish life its rhythm and depth. From the Torah’s first image of God dividing the waters, to the parting of the Sea of Reeds, water flows as a powerful thread through Jewish history. It is a symbol of renewal, resilience, and the promise of growth. Just as water nourishes the earth, hope nourishes the soul—quietly persistent, deeply powerful, and capable of shaping the landscape of our lives. In the year ahead, may we look for the moments of hope that make us stronger. May that hope—like water—flow freely, bringing healing, possibility, and connection to all it touches. We are pleased to provide you with a complimentary Jewish calendar for 5786. Hillside’s calendar will help you observe Jewish holidays, weekly Parsha, candle lighting times, and other important traditions. Request Your Calendar Here

Shofar horn rests on an open book, both illuminated with warm light, against a plain background.

The Jewish New Year: A Time for Reflection and Renewal

August 19, 2025

As the Jewish year of 5786 approaches, the turning of the calendar offers more than just a date change—it invites us into a sacred cycle of learning, reflection, and growth. In Judaism, each year is an opportunity to reconnect with our traditions, our community, and ourselves. Hillside Memorial Park and Mortuary spoke with Sarah Grondlund Jacob, our Community Liaison, to explore the deeper meaning of this moment in the Jewish year, as well as how this year’s calendar theme, Hatikvah —“The Hope”—inspires us to move forward together. A Year in the Life of the Torah At its most fundamental level, the Jewish year represents a complete cycle of reading the Torah from beginning to end. “The one thing that always happens,” Sarah explains, “is that it starts and ends with the beginning and the end of the Torah. And each week, we progress one Torah portion forward.” This steady rhythm ties the passage of time to the foundation of Jewish life and ensures that, throughout the year, we encounter the full breadth of Jewish teaching—whether or not the Torah portion aligns with the season in which the events took place. Marking Time by the Moon The Jewish calendar follows the lunar cycle, with each new month beginning at the Rosh Chodesh —the appearance of a new moon. Sarah notes the beauty of this symbolism: “It’s not actually a new moon; it’s the same moon that was just a sliver a few days ago. It disappears, but we have this confidence it will come back.” Unlike the unchanging sun, the moon waxes and wanes, reminding us that change and renewal are part of life. This cycle shapes not only our months but also the timing of our holidays, weaving the natural world into the spiritual rhythm of the year. Preparing the Heart for the New Year While Rosh Hashanah marks the formal beginning of the Jewish year, preparation begins a month earlier during Elul . This is a time for self-examination and tshuva —returning to one’s best self. “You have the ability to go to someone you’ve hurt, say you’re sorry, and change for the better,” Sarah says. “You’re not stuck in a cycle of hurting someone again and again.” The practice of seeking forgiveness, making amends, and setting intentions for the year ahead transforms the High Holy Days into a deeply personal journey toward growth and reconciliation. The Enduring Power of Hope This year’s Hillside calendar takes inspiration from Hatikvah , Israel’s national anthem, whose name means “The Hope.” For Sarah, the theme resonates beyond national borders. “Even now that we have Israel as a homeland, it’s not guaranteed—it’s something we continue to hope for and nurture. That hope keeps going.” She reflects on the idea of Jewish “peoplehood,” which transcends geography and observance levels: “We are still the same people, even with differences. The hope is for the continuation of this peoplehood.” Looking Ahead with Intention As we begin 5786, the Jewish New Year invites us to embrace the cycles that define our lives—of study, of renewal, of relationship, and of hope. Whether we look to the steady return of the moon, the rhythm of Torah readings, or the call of Hatikvah , each offers a reminder that the year ahead is a gift and a responsibility. We invite you to begin the new year with our 5786 calendar to mark Jewish holidays throughout the year, parsha candle lighting times, and more.