How Public Holidays Are Decided: A Look at Four Different Systems
A public holiday feels like a simple, fixed fact — offices close, banks shut, everyone knows the date in advance. In practice, how a date becomes an official holiday varies a lot from country to country, and understanding the difference explains why some holidays on our holiday pages show a confirmed date months in advance while others are marked "estimated" until closer to the day.
India: national holidays plus state-by-state variation
India recognizes just three official national holidays — Republic Day, Independence Day, and Gandhi Jayanti — all on fixed Gregorian dates. Beyond that, the central government publishes an annual list of "gazetted" holidays (covering things like Diwali, Holi and Eid), and individual states add their own regional and festival holidays on top. Many of these dates depend on the Hindu lunisolar calendar or the Islamic Hijri calendar, both of which are tied to astronomical observation rather than a fixed Gregorian date — which is why a Diwali or Eid date published a year in advance is usually a well-informed calculation rather than a government-confirmed certainty until it's closer.
United States: an act of Congress
Federal holidays in the US are set by federal law — Congress designates them by statute, and they apply to federal offices, banks and (via strong convention rather than law) most private employers. Since the US uses only the Gregorian calendar for federal holidays, dates are fixed and predictable years in advance — either a specific calendar date (July 4th for Independence Day) or a rule like "the fourth Thursday in November" for Thanksgiving.
United Kingdom: royal proclamation and government announcement
UK bank holidays have an unusually formal origin: they trace back to the Bank Holidays Act of 1871, and to this day some are confirmed each year by royal proclamation, with the government announcing the specific dates — particularly relevant when a fixed-date holiday would otherwise fall on a weekend and needs a substitute weekday. England & Wales, Scotland, and Northern Ireland each have a slightly different list, since a few holidays (like St Andrew's Day in Scotland) are regional rather than UK-wide.
UAE: confirmed close to the date, by design
The UAE's civil holidays (New Year's Day, National Day) have fixed Gregorian dates and are confirmed well in advance. Its Islamic holidays — Eid al-Fitr, Eid al-Adha, and others — follow the Hijri lunar calendar, whose months begin with the sighting of the new moon. Because moon sighting can't be certified with certainty far in advance, the UAE government (and other countries that use Hijri-based holidays) typically confirms the exact Gregorian date only days before the holiday itself, even though a reasonably accurate estimate is usually possible months ahead using astronomical calculation.
What this means for the dates on this site
We follow one simple rule across every country we cover: fixed, government-set dates are shown as-is, and anything that depends on lunar observation or a not-yet-published government announcement is clearly marked "estimated" until we can confirm it. You can see exactly how we approach this on our Data Sources page, and if you ever spot a date that needs correcting, our Corrections page explains how to tell us.