Spring arrives twice in Ireland: on March 1 for weather records and around March 20 for sky watchers. The difference between these two definitions creates a practical fork for anyone planning events, planting crops, or just tracking the seasons.

4 related posts

Astronomical spring 2024 (Northern Hemisphere): March 19 at 11:06 p.m. EDT · Meteorological spring start (Northern Hemisphere): March 1 · Spring 2024 in Ireland (meteorological): March 1 · Vernal Equinox 2024 date: March 19 · Spring equinox 2026 date: March 20

Quick snapshot

1Confirmed facts
2What’s unclear
3Timeline signal
  • Meteorological spring: 1 March (annual)
  • Vernal equinox 2024: 19 March (US) / 20 March (Ireland)
  • Vernal equinox 2026: 20 March
  • Leap year 2024 pushed the equinox to 19 March — the earliest in 128 years
4What’s next
  • Search interest in “when does spring start 2025” will peak around March 2025
  • Meteorological spring will begin on 1 March 2025, as always
  • The astronomical equinox in 2025 is expected to fall on 20 March, pending official confirmation

The table below shows the key dates for the coming years, highlighting the drift caused by leap year mechanics.

Year Vernal Equinox (Northern Hemisphere) Meteorological Spring Start
2024 19 March at 11:06 p.m. EDT (20 March in Ireland) 1 March
2025 20 March (pending official confirmation) 1 March
2026 20 March (Farmers’ Almanac (US almanac)) 1 March

The pattern is clear: the astronomical date varies, while the meteorological date stays fixed — a useful distinction for climate tracking and seasonal planning.

When exactly is spring 2024?

The answer depends on which calendar you use. According to Met Éireann (Ireland’s national meteorological service), meteorological spring begins on 1 March and covers March, April and May. Astronomically, the vernal equinox marks the start of spring. In 2024, that equinox occurred on 19 March at 11:06 p.m. EDT (equivalent to 3:06 a.m. UTC on 20 March), making 20 March the first day of astronomical spring in Ireland (Belfast Telegraph (Northern Ireland news outlet)).

Meteorological spring begins on 1 March each year, providing a consistent reference for climate statistics.

— Met Éireann

The upshot

For anyone planning events or tracking seasons, the gap between the two definitions means you get two spring start dates — one fixed, one shifting.

What is the difference between meteorological spring and astronomical spring?

Astronomical spring is defined by the Earth’s orbit around the Sun. The vernal equinox occurs when the Sun crosses the celestial equator, making day and night nearly equal in length. This event falls between 19 and 21 March (Belfast Telegraph (Northern Ireland news outlet)). Meteorological spring, by contrast, is fixed to the calendar: 1 March always starts the season, because it aligns with the climate-recording months of March, April and May, as Met Éireann (Ireland’s national meteorological service) explains. The advantage of the meteorological system is consistency — it allows meteorologists to compare seasonal data across years without the calendar noise of orbital mechanics.

Five key differences, one pattern: astronomical spring is variable, meteorological spring is fixed.

Aspect Astronomical Spring Meteorological Spring
Definition Based on Earth’s tilt and orbit (equinox) Based on calendar months
Start date variation 19–21 March (varies year to year) 1 March (fixed every year)
Used by Astronomers, some cultural traditions Meteorologists, climate researchers
Length Until summer solstice (~20–21 June) Three calendar months (Mar–May)
Why exists Celestial alignment Standardised climate records

The implication: astronomical spring is more accurate to seasonality in terms of daylight, but meteorological spring is more practical for data collection and everyday planning.

Is March 21 always the first day of spring?

No — and it hasn’t been true for decades. The equinox date drifts because the Earth’s orbit takes approximately 365.25 days, so the equinox occurs about 6 hours later each common year, resetting on leap years (Irish Examiner (Irish daily newspaper)). In 2024, a leap year, the equinox landed on 19 March, the earliest in 128 years. In 2025 and 2026 it returns to 20 March.

What month is spring in Ireland?

In Ireland, the official meteorological definition — used by Met Éireann (Ireland’s national meteorological service) — treats March, April and May as spring. This aligns with the general Northern Hemisphere convention. Astronomical spring, however, begins around 20 March and runs to the summer solstice on 20 June. Some Irish cultural traditions recognise St. Brigid’s Day (1 February) as the start of spring, though this is not an official meteorological or astronomical designation (Met Éireann (Ireland’s national meteorological service)).

  • Meteorological spring (official): March, April, May (1 March start)
  • Astronomical spring: from equinox (20 March 2024) to summer solstice
  • Cultural tradition: some mark spring from 1 February (St. Brigid’s Day)
Why this matters

For Irish farmers, gardeners and tourism operators, the gap between the two starts means they must decide which calendar to follow for planting, events and marketing.

Is 1 March officially spring?

Officially, yes — in meteorological terms. Met Éireann (Ireland’s national meteorological service) and the UK Met Office both adopt 1 March as the start of spring for record-keeping. The astronomical community recognises the equinox as the true seasonal marker, meaning 20 March is the official astronomical first day of spring in Ireland for 2024 (Belfast Telegraph (Northern Ireland news outlet)).

What day is the first day of spring 2026?

According to the Farmers’ Almanac (US almanac), the spring equinox in 2026 will occur on 20 March. Because 2026 is not a leap year, the equinox returns to the more common 20 March date, after the leap-year-induced 19 March date in 2024. Meteorological spring will again begin on 1 March 2026, as it does every year.

Spring 2024 was very mild, wet and dull overall, according to Met Éireann’s climate statement.

— Met Éireann, Spring 2024 Climate Statement (Met Éireann (Ireland’s national meteorological service))

What is the official 1st day of spring?

There is no single official definition. The United Nations and most national meteorological services adopt the meteorological definition for climate purposes, while astronomical organisations and many cultural calendars follow the equinox. In Ireland, Met Éireann (Ireland’s national meteorological service) uses 1 March as the official start of spring for all its climate statements — such as the Spring 2024 Climate Statement published on 1 June 2024 (Met Éireann (Ireland’s national meteorological service)).

Bottom line: The first day of spring is not a fixed universal date. Irish weather services use 1 March for consistency; astronomers and almanacs use the equinox (19–21 March). For event planners, go with 1 March. For daylight enthusiasts, follow the equinox.

Spring timeline: key dates

  • 1 March (annually): Meteorological spring begins
  • 19 March 2024: Vernal equinox (US time) — astronautically earliest since 1896
  • 20 March 2024: Vernal equinox in Ireland — astronomical spring begins
  • 20 June 2024: Summer solstice — astronomical spring ends
  • 20 March 2026: Next equinox confirming pattern (Farmers’ Almanac (US almanac))

What is confirmed and what remains unclear

Confirmed facts

  • Astronomical spring 2024 in Ireland began on 20 March (Belfast Telegraph (Northern Ireland news outlet))
  • Meteorological spring begins on 1 March each year (Met Éireann (Ireland’s national meteorological service))
  • Spring equinox 2026 is on 20 March (Farmers’ Almanac (US almanac))

What’s unclear

  • Whether the public predominantly uses astronomical or meteorological definitions varies by culture (Irish Examiner (Irish daily newspaper))
  • Exact date of equinox 2025 needs official confirmation from astronomical authority
  • Some Irish traditions consider February spring, but this has no official status (Met Éireann (Ireland’s national meteorological service))
Additional sources

met.ie, sunrisesunsettime.org, drikpanchang.com, climatecouncil.ie, met.ie, met.ie, holidays-info.com, rte.ie, thejournal.ie

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Frequently asked questions

When does spring start in 2024?

Meteorological spring began on 1 March 2024. Astronomical spring in Ireland began on 20 March 2024, following the vernal equinox.

What is the vernal equinox?

The vernal equinox is the moment the Sun crosses the celestial equator, making day and night nearly equal in length. It marks the astronomical start of spring (Belfast Telegraph (Northern Ireland news outlet)).

Why does the first day of spring change dates?

Because the Earth’s orbit takes about 365.25 days, the equinox shifts about 6 hours later each common year. Leap years reset the timing, causing the date to vary between 19 and 21 March (Irish Examiner (Irish daily newspaper)).

Is spring 2024 starting earlier than usual?

Yes — the 19 March equinox (US time) is the earliest since 1896, due to the leap year cycle.

What are the spring months in the Northern Hemisphere?

March, April and May (meteorological definition). Astronomically, spring runs from the vernal equinox (19–21 March) to the summer solstice (~20–21 June).

Do all countries define spring the same way?

No. The meteorological definition (1 March start) is used by most weather services, but many countries follow astronomical or cultural calendars. In Ireland, the official start is 1 March for climate records (Met Éireann (Ireland’s national meteorological service)).

For anyone navigating Ireland’s spring, the two definitions create a practical fork: 1 March for weather data, 20 March for daylight. The implication for event planners and farmers is clear: lock in 1 March as the operational start, or align with the equinox for maximum sunlight — but don’t assume the two are the same.