Why holiday dates move every year
Most of the world's largest public holidays are not dated by the Gregorian calendar. Eight other systems set them, and two of those produce dates that are confirmed only days in advance.
Holiday dates move because most of the world's major holidays are not set by the Gregorian calendar. Five other systems decide them: the Hijri calendar, which is purely lunar; the Chinese and Korean lunisolar calendars; the Hindu and Buddhist lunisolar calendars; the Hebrew calendar; and the Easter computus, which exists in a Gregorian and a Julian form.
The practical consequence is that a holiday date published a year ahead is a calculation, and in some cases a prediction. Islamic dates in particular depend on the new moon being sighted, which means the official date can differ between two neighbouring countries observing the same holiday.
In numbers: across the 1,345 nationwide public holidays we hold for the 100 countries on this site, 448 named holidays fall on a different day in 2027 than they do in 2026, and 95 of the 100 countries have at least one that moves. This is not a fringe case — in most of Asia, the Middle East and North Africa the largest holiday of the year is a moving one.
| Calendar | How it works | What it moves |
|---|---|---|
| Hijri (Islamic) | Purely lunar, about 354 days, no leap month | Eid al-Fitr, Eid al-Adha, Ramadan, Islamic New Year, Mawlid — each falls about 11 days earlier every Gregorian year |
| Chinese and Korean lunisolar | Lunar months corrected to the solar year by a leap month | Lunar New Year, Seollal, Chuseok, Mid-Autumn Festival — stays in the same season, moves within a month-wide window |
| Vietnamese lunisolar | As the Chinese calendar but reckoned in Vietnamese local time | Tết, which can fall a day apart from Chinese New Year |
| Hindu and Buddhist lunisolar | Lunar months with intercalation, regionally variant | Diwali, Holi, Vesak, Poya days — some observed on different days in different states |
| Hebrew | Lunisolar with a fixed 19-year leap cycle | Rosh Hashanah, Yom Kippur, Passover — predictable far ahead, but drifting against the Gregorian date |
| Easter computus (Gregorian) | First Sunday after the first full moon on or after 21 March | Good Friday, Easter Monday, Ascension, Pentecost, Corpus Christi, Carnival |
| Easter computus (Julian) | The same rule applied to the Julian calendar | Orthodox Easter and everything dated from it — usually later than the Western date, by up to five weeks |
| Bikram Sambat | Solar calendar used officially in Nepal, about 57 years ahead | Nepali New Year, which falls in April |
The eight dating systems behind the moving holidays in the countries we cover.
Why this matters for any holiday dataset
Almost every free holiday dataset is built around fixed Gregorian dates, and handles the moving ones badly or not at all. That is not a small gap: the largest holiday of the year is a moving one across most of Asia, the Middle East and North Africa. A list of Vietnamese holidays without Tết is missing the week the country stops. A list for the Philippines, Indonesia or Egypt without Eid is missing the same thing.
We know the size of the gap because we measured it. Our own dataset used to have it: an earlier version of these pages carried no counts at all because the file behind them was missing Tet, both Eids in the Philippines, and every Islamic holiday in Egypt and Tunisia. Rebuilding it from each country's rules rather than from a scraped list added 232 dates and removed 356, and moved the count for 76 of the 100 countries. In the rebuilt file, 448 of the 1,345 nationwide public holidays are named holidays set by a calendar other than the Gregorian one — 95 of the 100 countries have at least one, and only Armenia, Laos, Montenegro and Uruguay have none. Sri Lanka we cannot say either way: its Poya days are gazetted a year at a time and 2027 has not been published. A dataset that handles moving holidays badly is not making a small error.
Where a holiday is set by one of the calendars above, treat any date published far in advance as calculated rather than confirmed. 76 dates in our 2026 file are marked estimated for exactly that reason: they follow the Islamic calendar and the official day is fixed only when the new moon is sighted. Check the national announcement close to the day before you commit to travel.
Sighting versus calculation
Two countries can observe the same Islamic holiday on different days without either being wrong. Where the month begins on confirmed naked-eye sighting of the new crescent, weather and geography decide the answer, and the announcement comes the evening before. Where it begins by astronomical calculation, the date is fixed years ahead. Both approaches are in use, sometimes within the same region, which is why a single global Eid date does not exist.
The countries whose calendars move the most
| Country | Holidays that move | Holidays in 2026 | Dates marked estimated |
|---|---|---|---|
| 🇳🇵 Nepal | 16 | 32 | 2 |
| 🇨🇴 Colombia | 13 | 19 | — |
| 🇮🇳 India | 12 | 18 | — |
| 🇮🇩 Indonesia | 12 | 17 | — |
| 🇪🇬 Egypt | 10 | 16 | 5 |
| 🇮🇸 Iceland | 9 | 14 | — |
| 🇲🇾 Malaysia | 9 | 14 | — |
| 🇰🇷 South Korea | 9 | 22 | — |
| 🇫🇮 Finland | 8 | 15 | — |
| 🇮🇱 Israel | 8 | 9 | — |
| 🇯🇴 Jordan | 8 | 14 | 10 |
| 🇦🇷 Argentina | 7 | 19 | — |
| 🇧🇿 Belize | 7 | 14 | — |
| 🇩🇰 Denmark | 7 | 10 | — |
| 🇫🇯 Fiji | 7 | 12 | 2 |
| 🇭🇰 Hong Kong | 7 | 15 | — |
| 🇲🇺 Mauritius | 7 | 15 | 1 |
| 🇵🇭 Philippines | 7 | 20 | — |
| 🇸🇪 Sweden | 7 | 13 | — |
| 🇦🇪 United Arab Emirates | 7 | 12 | 9 |
The 20 countries with the most holidays set by a calendar other than the Gregorian one, found by comparing each holiday's 2026 date with its 2027 date. The middle column counts distinct dates off in 2026; the first counts named holidays, so a festival running several days counts once. The last counts dates that depend on sighting the new moon and are therefore not final.
Common follow-up questions
Why does Eid move earlier every year?
The Hijri calendar is purely lunar and has no leap month, so its year is about eleven days shorter than the Gregorian year. Islamic holidays therefore fall about eleven days earlier each year and cycle through the seasons over roughly 33 years.
Why does Lunar New Year stay in winter when Eid does not?
Because the Chinese calendar is lunisolar rather than lunar. It inserts a leap month periodically to keep the months aligned with the solar year, so the date moves within a window of about a month but never drifts out of season.
How far ahead can a holiday date be trusted?
Gregorian fixed dates and Easter-derived dates can be calculated exactly, for any year. Hebrew and Chinese lunisolar dates are also calculable far ahead. Islamic dates where the month starts on moon sighting are announced within a day or two of the event, so anything published earlier is a calculated estimate.
Why is Orthodox Easter usually later than Western Easter?
Both use the same rule but apply it to different calendars. The Orthodox computus works from the Julian calendar, which now runs thirteen days behind the Gregorian one, and also requires Easter to follow Passover. The gap between the two dates ranges from zero to five weeks.