Holiday guide
Why public holiday dates change every year
Learn why Easter-based holidays, lunar calendars and substitute days move around the calendar.
Some holidays always use the same calendar date, while others move from year to year. The reason usually lies in the calendar or legal rule used to determine them.
Religious calendars
Easter and holidays linked to it follow an ecclesiastical calculation, so their Gregorian dates change. Islamic holidays follow a lunar calendar and move earlier through the seasons over time.
Substitute and in-lieu days
Some countries move the day off when a holiday falls on a weekend. The original observance and the substitute day may both appear in a detailed calendar.
One country, several rules
States, provinces, cantons and cities may set additional holidays. This is why checking both the year and the regional scope matters when planning work or travel.