When Is the First Day of Spring? 2026 Dates & Traditions

Sooner or later, everyone looks up the date for the first day of spring — only to find three different answers. In 2026, astronomical spring begins on March 20 according to the Royal Museums Greenwich (UK national observatory), while meteorological spring has already started on March 1. Then there’s the older Celtic tradition that puts spring’s start on February 1. Let’s sort out which one applies to you.

Astronomical spring start range: March 19–21 each year · Meteorological spring start: Always March 1 · Traditional Irish spring start: February 1 (St. Brigid’s Day) · Spring equinox 2026 date: March 20, 2026

Five key facts — one pattern: spring’s official start depends on which calendar you use, and the three definitions rarely agree.

What is the actual first day of spring?

Astronomical spring: the vernal equinox

• Astronomical spring begins on the spring equinox, which in the Northern Hemisphere falls between March 19 and 21 each year (Met Office (UK national weather service)).
• The equinox marks when the Sun crosses the celestial equator, making day and night nearly equal — about 12 hours each (Royal Museums Greenwich).

The implication: this is the classic calendar definition, but its shifting date catches people off guard every year.

Meteorological spring: fixed March 1

• Meteorological spring always starts on March 1 and ends on May 31 (Met Office).
• It’s based on annual temperature cycles, making weather records consistent and comparable across years (Met Éireann).

Why this matters: if you’re tracking climate data or planning a season-long project, March 1 is the reliable anchor.

Why multiple definitions exist

• Astronomical seasons align with Earth’s orbit; meteorological seasons align with the temperature cycle (Met Éireann).
• Different cultures also have their own traditions, such as Ireland’s February 1 start (Rabbie’s Tours (travel & culture guide)).

The pattern: the definition you choose determines when your spring actually begins, so the answer shifts depending on your context.

Is the first day of spring always March 20?

Equinox variability: why dates shift

• The spring equinox can fall on March 19, 20, or 21 because the Earth’s orbital year is about 365.24 days (Farmers’ Almanac).
• Leap years and the Gregorian calendar’s drift cause the date to slide (Royal Museums Greenwich).

The trade-off: most people assume March 21, but in recent decades it’s almost always March 19 or 20.

Specific dates for 2026, 2027, and 2028

• 2026: March 20 at 14:46 UTC (Farmers’ Almanac).
• 2027: March 20 at 20:25 UTC (EarthSky).
• 2028: The spring equinox is predicted for March 19 (Royal Museums Greenwich).

Time zones and local date changes

• Because the equinox occurs at a single universal moment (UTC), local time may shift the calendar date. In the UK (UTC+0 in March), the equinox remains March 20 in 2026 and 2027 (Farmers’ Almanac).

The pattern: March 20 is the dominant date now, but March 19 occurs roughly once per four-year leap cycle, and March 21 is rare but not extinct (last in 2007, next in 2102).

What is the first day of spring in Ireland?

Traditional Irish spring: February 1 (St. Brigid’s Day)

• In Irish tradition, spring starts on February 1, associated with St. Brigid’s Day and the Celtic calendar’s cross-quarter day (My Irish Jeweler).
• This view places spring in February, March, and April — a three-month span that matches the growth cycle in Ireland’s mild climate (Rabbie’s Tours).

Meteorological spring in Ireland: March 1

• Met Éireann officially uses March 1 as the start of meteorological spring (Met Éireann).
• The Irish weather service acknowledges that people in Ireland use multiple systems — including the vernal equinox and St. Brigid’s Day — depending on the context (Met Éireann).

Astronomical spring date for Ireland

• Ireland’s astronomical spring begins on the same equinox as the UK — March 20 in 2026 and 2027 (Royal Museums Greenwich).

What this means: Ireland’s layered calendar traditions reflect a culture that blends ancient agricultural rhythms with modern meteorological science.

What is a fun fact about the first day of spring?

Egg balancing myth

• The popular claim that you can balance an egg only on the equinox is a myth; you can actually do it any day of the year (EarthSky).
• Still, the equinox remains a popular time for this trick because of the folklore that the Sun’s gravitational pull creates a temporary balance.

Equal day and night (nearly)

• On the spring equinox, day and night are approximately equal in length — about 12 hours each — but not perfectly equal because of atmospheric refraction (Royal Museums Greenwich).
• True equality occurs a few days before the equinox, depending on latitude.

Cultural celebrations worldwide

• Nowruz (Persian New Year) is celebrated on the equinox, and Ostara (a pagan festival) marks the season’s turn (Farmers’ Almanac).
• In Ireland, the spring equinox is less celebrated than St. Brigid’s Day, but the lengthening days are universally observed.

The implication: the equinox is a cultural as well as astronomical milestone, even if the egg trick doesn’t need it.

Why is 21st March and 23rd?

Equinox and solstice patterns

• Equinoxes occur around March 20–21 and September 22–23, but the dates drift because the tropical year is 365.2422 days (Royal Museums Greenwich).
• The “spring equinox on March 21” is an older reference from before modern calendar adjustments.

Gregorian calendar alignment

• The Gregorian calendar has leap years to keep the equinox close to March 20, but small residuals accumulate (Farmers’ Almanac).
• The last March 21 equinox in the Northern Hemisphere was 2007; the next will not occur until 2102 (EarthSky).

Why the date varies

• The equinox date shifts due to Earth’s elliptical orbit and the difference between calendar year and orbital year (Royal Museums Greenwich).
• March 23 is extremely rare — it hasn’t happened in modern times — but it can occur if the equinox falls just after midnight UTC and local calendars shift.

The catch: the idea of a fixed spring start is an illusion; the equinox moves within a narrow window, and human calendars only approximate it.

Three definitions, one pattern: each system serves a different purpose — astronomy, weather, or culture.

The pattern: using the astronomical definition gives you the classic “first day” but a shifting date; the meteorological definition is predictable; the Irish tradition ties to heritage. Pick the one that fits your purpose.

For anyone in Ireland or the UK wondering when spring really begins, the answer depends on your calendar: if you’re planning a garden, meteorological spring gives you a reliable starting point; if you’re following tradition, February 1 has deep roots. The astronomical equinox, while poetically satisfying, is the most variable — but now you know exactly when it falls for 2026 and 2027.

For a detailed breakdown of the astronomical and meteorological start dates, you can refer to our guide on spring 2026 dates for multiple years.

Frequently asked questions

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