A Haft-Seen table for Nowruz at the U.S. Department of State in Washington, D.C.

Why Is Nowruz Sometimes March 20 and Sometimes March 21?

Nowruz is tied to the arrival of spring, yet invitations, calendars, and search results do not always agree on whether Persian New Year is March 20 or March 21. Neither date is universally correct. The answer changes because Nowruz follows an astronomical event—the March equinox—while March 20 and 21 belong to the separate Gregorian calendar.

The short answer: the equinox happens at one precise instant, but that instant shifts on the Gregorian clock from year to year. Iran’s Solar Hijri calendar places the first day of Farvardin at the midnight closest to the equinox, calculated for Iran’s reference meridian. Depending on the equinox time, 1 Farvardin can therefore correspond to March 20 or March 21.

Nowruz is an astronomical New Year

The word Nowruz (نوروز) means “new day.” In Iran’s calendar it is not simply assigned to “the third Thursday of March” or another fixed Gregorian rule. It marks the opening of Farvardin and the Solar Hijri year at the spring equinox.

The U.S. Naval Observatory defines an equinox as the moment that marks the beginning of spring or fall and provides calculated dates and times for the years 1700–2100. At the March equinox, the Sun crosses the celestial equator from south to north. It is one instant worldwide, even though clocks in Tehran, Toronto, Los Angeles, and London display different local times.

For a general introduction to the holiday’s customs, visit What Is Nowruz?. This article focuses on the narrower calendar question: why its Gregorian date moves.

Why the equinox time changes each year

Earth does not complete its orbit in exactly 365 days. A tropical year—the seasonal cycle from one March equinox to the next—is about 365 days plus nearly six hours. A common Gregorian year has only 365 days, so the next equinox usually appears several hours later on the clock. A leap day then pushes the clock time substantially earlier.

That repeating adjustment prevents the seasons from drifting far through the Gregorian calendar, but it does not pin the equinox to one date and time. The March equinox normally arrives on March 20 and can occur near the boundary with March 19 or 21. The Persian calendar responds to the actual astronomical calculation rather than permanently choosing one Gregorian date.

How Iran turns an instant into New Year’s Day

An astronomical instant has no duration, but a calendar day lasts from midnight to midnight. Iran therefore needs a rule that converts the equinox into the civil date 1 Farvardin.

Standard descriptions of the modern Iranian calendar place New Year at the midnight nearest the equinox, using the Iranian reference meridian at 52.5° east. In practical terms:

  • If the equinox occurs before local noon, the nearer midnight is the one that began that day.
  • If the equinox occurs after local noon, the nearer midnight is the one beginning the following day.

This noon boundary is why “the equinox happened on March 20” and “1 Farvardin is March 21” can both be true. The first statement names the instant on a clock; the second names the Iranian civil day selected by the calendar.

The timeanddate.com explanation of the Solar Hijri calendar describes its equinox-based structure and Iranian reference meridian. For the official printed calendar, Iran’s national dates are prepared by the Calendar Center at the University of Tehran’s Institute of Geophysics.

Why Nowruz 1405 began on March 21, 2026

The U.S. Naval Observatory’s 2026 calculation places the March equinox at 14:46 UTC on March 20. That was 6:16 p.m. in Iran. Because the equinox occurred after local noon, the nearer midnight was the beginning of March 21.

Accordingly, the official Iranian calendar for 1405 lists 1 Farvardin 1405 on Saturday, March 21, 2026.

What about Nowruz 1406 in 2027?

The March equinox in 2027 is calculated for Saturday, March 20 at 20:24 UTC, according to timeanddate.com’s 2027 equinox calculation. Under current Iranian time-zone rules, that is 11:54 p.m. in Iran—only six minutes before midnight. The nearest midnight is therefore the start of Sunday, March 21.

That makes 1 Farvardin 1406 Sunday, March 21, 2027. Our separate Persian Calendar 1406 guide distinguishes predictable calendar structure from the official holiday details that still require publication by Iranian authorities.

2026 and 2027 at a glance

Persian year March equinox Time in Iran 1 Farvardin
1405 March 20, 2026 at 14:46 UTC 6:16 p.m. March 21, 2026
1406 March 20, 2027 at 20:24 UTC 11:54 p.m. March 21, 2027

The local-time conversions above use the time-zone rules in force when this article was published. The astronomical instant is independent of civil time-zone policy.

Why some people celebrate on March 20 anyway

There are several reasons March 20 still appears in Nowruz messages even when Iran’s 1 Farvardin is March 21:

  • The equinox itself may occur on March 20. Families often count down to the exact saal tahvil, or turning of the year, wherever they live.
  • Time zones change the local clock. A late-night March 20 equinox in Iran may still be afternoon in Canada or the United States.
  • Public events need convenient schedules. Community celebrations may be held on the nearest weekend rather than at the astronomical instant.
  • English-language shorthand simplifies the holiday. Some announcements call March 20 “Nowruz” even when the formal Iranian calendar date begins at the following midnight.

For diaspora families, the clearest invitation includes both pieces of information: the exact equinox time in the guest’s time zone and the date of the gathering.

Isn’t International Nowruz Day always March 21?

Yes—but that is a fixed international observance, not a replacement for the astronomical rule. In 2010, the United Nations General Assembly adopted Resolution 64/253, recognizing March 21 as the International Day of Nowruz. The UN uses one stable date for worldwide recognition, while the Iranian civil calendar continues to determine 1 Farvardin astronomically.

The difference is similar to having an official awareness day for a seasonal event: the commemorative date stays fixed even though the precise astronomical moment moves.

How to avoid a one-day calendar mistake

  1. Check an official Iranian calendar for the Solar Hijri civil date.
  2. Use an astronomical source for the exact equinox time.
  3. Convert that instant into your local time zone before sending invitations.
  4. Write both dates: for example, “1 Farvardin 1406 / March 21, 2027.”

For everyday conversions, use Tute’s Persian Date Converter. If you are learning the calendar itself, our guide to the meanings of the Persian month names explains Farvardin through Esfand.

Keeping both calendars visible

A dual-calendar reference is especially useful for Iranian households abroad, where school, work, and appointments follow the Gregorian calendar while birthdays, memorials, and cultural holidays may be remembered in Solar Hijri dates.

The Persian Hijri Shamsi Desk Calendar 1405 covers March 2026 through February 2027. For the following year, the Persian Hijri Shamsi Desk Calendar 1406 covers March 2027 through February 2028. Both pair Iranian dates with familiar planning space and landmark imagery.

Frequently asked questions

Is Nowruz always at the exact moment of the equinox?

The traditional countdown centers on the exact equinox, or saal tahvil. The official calendar date 1 Farvardin is a full civil day selected in relation to that instant. The moment and the date are connected, but they are not identical concepts.

Can Nowruz be March 19?

The March equinox can fall on March 19 in UTC in some years. Whether Iran’s 1 Farvardin corresponds to March 19 or 20 depends on the equinox time under the Iranian calendar rule. For contemporary planning, always consult the calendar for the specific year rather than extrapolating from the previous one.

Why doesn’t leap year alone tell me the date?

Leap years explain much of the recurring shift, but the exact equinox depends on astronomical calculation, and the Iranian date also depends on where the instant falls relative to the local noon boundary. A simple “every four years” shortcut is therefore unreliable.

Sources and image credit

Image: A Haft-Seen sofreh outside the U.S. Secretary of State’s office at the Harry S. Truman Building in Washington, D.C., photographed by the U.S. Department of State on March 20, 2014. The photograph is a public-domain U.S. federal government work, obtained via Wikimedia Commons. No changes made.

Zurück zum Blog