Answers to the holiday-date questions people ask most.
Why does Easter fall on a different date every year?
Unlike most holidays on this list, Easter isn't tied to a fixed date — it's tied to the moon. It's defined as the first Sunday after the first full moon following the spring equinox, a rule set by the Council of Nicaea in 325 AD. Because full moons don't line up neatly with our calendar, Easter can land anywhere between March 22 and April 25.
Why do Orthodox Christians celebrate Christmas on January 7 instead of December 25?
It comes down to which calendar is being used. In 1582, Pope Gregory XIII introduced the Gregorian calendar to correct drift in the older Julian calendar, but many Orthodox churches never adopted it. Because the Julian calendar has since drifted 13 days behind the Gregorian one, "December 25" on the Julian calendar now falls on January 7 by the calendar most of the world uses.
Is New Year's Day on January 1st everywhere in the world?
Not universally. January 1 is specifically the start of the Gregorian calendar year, which much of the world uses for civil purposes, but it's far from the only new year celebrated. Lunar New Year (celebrated across much of East and Southeast Asia) typically falls in late January or February, Nowruz marks the Persian new year at the spring equinox, and Rosh Hashanah, the Jewish new year, usually falls in September.
Why does Thanksgiving fall on a Thursday, and has it always been the fourth Thursday of November?
Thanksgiving has been fixed as the fourth Thursday of November since 1941, but it wasn't always so simple. In 1939, President Franklin D. Roosevelt tried moving it a week earlier to lengthen the holiday shopping season — a change so unpopular it was nicknamed "Franksgiving." After two years of confusion (some states kept the old date, some followed the new one, a few celebrated both), Congress passed a law permanently setting the fourth Thursday of November as the official date.
Why do Americans eat corned beef and cabbage on St. Patrick's Day if it's not a traditional Irish dish?
It's actually an Irish-American invention, not something eaten in Ireland. Irish immigrants in 19th-century cities like New York and Boston couldn't easily get the salted pork they'd eaten back home, but they lived alongside Jewish delis selling affordable kosher corned beef — so they substituted it, paired it with cheap, easy-to-cook cabbage, and it became a point of pride for Irish-American communities.
Where did trick-or-treating come from?
It traces back to "guising" and "souling" — medieval customs where people, often the poor, went door to door in costume or offered prayers in exchange for food or coins around the Celtic festival of Samhain and All Saints' Day. The phrase "trick or treat" wasn't recorded until 1927, and the modern, candy-focused version of the tradition really took off in America in the 1930s–1950s as communities looked for a safer alternative to Halloween pranking and vandalism.
Why do we set off fireworks on the Fourth of July?
The tradition goes back to the very first Independence Day. On July 3, 1776, John Adams wrote to his wife predicting the anniversary should be marked with "Pomp and Parade... Bonfires and Illuminations" — and the following year, Philadelphia held the first organized celebration, complete with a fireworks display and ships firing 13-gun salutes for the original colonies. The custom has stuck ever since.