Why Passover dates change on the civil calendar

The Hebrew date stays the same

Passover begins on 15 Nisan every year in the Hebrew calendar. Its date changes on the Gregorian, or civil, calendar because the two calendars organize the year differently. The Jewish calendar is lunisolar: its months follow a lunar pattern, while adjustments keep its festivals aligned with the solar seasons. Passover’s movement across March and April is therefore a consequence of converting between calendars, not a change to its Hebrew date.

That distinction resolves a common planning puzzle. If last year’s family meal was in early April, you cannot obtain the next one simply by adding a civil year to your appointment. The annual observance follows Nisan. A good calendar entry should retain both the Hebrew festival date and the civil evening on which the observance begins, so you can recognize the relationship when checking another year.

Source notes: Hebcal · Passover 2026 and the 15 Nisan starting date · Maimonides · Sanctifying the New Moon, chapter 1

Why twelve lunar months need an adjustment

Maimonides begins his Laws of Sanctifying the New Moon by explaining the relationship between lunar months and solar years. Twelve lunar months are shorter than a solar year by roughly eleven days. If every Hebrew year consisted only of those twelve months, festivals would steadily move through the seasons. An added month in designated leap years addresses that difference and maintains the calendar’s seasonal relationship.

The added month is an Adar, producing Adar I and Adar II before Nisan. It is a whole month rather than a single extra day like February 29 in the civil calendar. Maimonides describes the calculated system’s repeating nineteen-year cycle, containing seven leap years. You do not need to calculate that cycle yourself to use the calendar, but knowing the mechanism explains why one year’s Passover can arrive noticeably later than the previous year’s.

Source notes: Maimonides · Sanctifying the New Moon, chapter 1 · Maimonides · Sanctifying the New Moon, chapter 6

Spring is a calendar reference point

The seasonal principle is tied to the spring setting of Passover in the Land of Israel. It does not mean the festival occurs in local spring for everyone around the world. A household in the southern hemisphere can observe the same Hebrew festival in its local autumn. The shared calendar remains anchored to its traditional seasonal reference rather than being recalculated to match each reader’s weather.

This is useful when reading online descriptions that simply call Passover a spring holiday. They describe the calendar’s historical and geographical setting. If you are writing an invitation for relatives in several countries, the clearest language gives the date, time, and place explicitly. You can appreciate the season’s imagery while making sure that the practical details are understandable to people in different climates and time zones.

Source notes: Maimonides · Sanctifying the New Moon, chapter 1

Check the starting evening as well as the date

Jewish holidays begin in the evening. A calendar may list the daytime civil date corresponding to 15 Nisan and separately identify the preceding evening as the holiday’s start. Those labels describe one observance from two angles. For example, Hebcal’s 2026 Diaspora page records Passover beginning on the evening of April 1. A civil calendar appointment for the first seder belongs on that starting evening.

Before sharing an event, decide whether you are recording the festival as an all-day calendar label or inviting people to a particular meal. The second requires an actual local time and address. A holiday listing does not automatically supply your family’s dinner time. For ritual start and end times, use a reliable calendar configured for the location and the conventions of the community hosting the observance.

Source notes: Hebcal · Passover 2026 and the 15 Nisan starting date · Hebcal · Israel, Diaspora and local-time calendar options

Choose the appropriate community schedule

Passover is observed for seven days in Israel, and for eight days in many traditional Diaspora communities. Most Reform Jews also use a seven-day observance, as the Union for Reform Judaism explains. A date range therefore needs its community context, especially when it is used to plan the final holiday days. Hebcal provides separate Israel and Diaspora schedules; its default API schedule is Diaspora unless the Israel option is selected.

Imagine that an event organizer in Jerusalem and a relative abroad share one calendar. Their opening evening can agree while their expected final holiday day differs. Labeling the calendar’s schedule prevents a genuine difference in observance from being mistaken for a conversion error. When a family custom differs from a general calendar listing, confirm the intended gathering dates with the host and keep those dates visible in the invitation.

Source notes: Hebcal · Passover 2026 and the 15 Nisan starting date · Hebcal · Israel, Diaspora and local-time calendar options · Union for Reform Judaism · Seven-day and eight-day Passover observances

Keep a reusable Passover planning record

A useful annual note contains the Hebrew year, 15 Nisan, the civil starting evening, the place, the community schedule, and the source checked. Add separate appointments for gatherings or preparation deadlines. This gives you enough context to update the plan next year instead of copying an old civil date and hoping it still fits. It also helps another person understand how you arrived at the date.

When a date looks surprising, check these details in order: correct year, correct schedule, and evening versus daytime label. Then compare it with a second reliable calendar or your community’s announcement. The durable lesson is simple: the festival is stable within its own calendar, while its civil date reflects lunar months, leap-month adjustments, and the evening boundary. Once those layers are visible, changing dates become easier to plan around.