When Does Spring Start in the UK? 2026 Dates Explained

If you’ve been waiting for longer evenings and the first crocuses to push through, you’ve probably wondered exactly when spring arrives in the UK. The honest answer? It depends on who you ask. Two official systems are in play, and they don’t always agree on the date.

Meteorological spring start: 1 March ·
Astronomical spring start: 20 March ·
Meteorological spring end: 31 May ·
Spring 2026 astronomical: 20 March

What is the first day of spring in the UK?

The UK has two official answers to this question, and both come from respected institutions. The Met Office (UK’s national weather service) puts meteorological spring on 1 March. The National Physical Laboratory, which tracks astronomical events, marks astronomical spring at the vernal equinox on 20 March 2026.

Meteorological definition

Meteorologists group the year into four fixed three-month seasons: March, April, and May become spring. This system aligns with the Gregorian calendar and temperature patterns, making it ideal for climate record-keeping. The Royal Meteorological Society notes that consistent boundaries let scientists compare data across decades without seasonal drift.

Astronomical definition

Astronomical spring begins when the sun crosses the celestial equator moving northward—the vernal equinox. At that moment, day and night are roughly equal everywhere on Earth. The 2026 equinox falls on 20 March, according to the National Physical Laboratory. Because the tropical year doesn’t divide evenly into days, the equinox date shifts by a day or two annually.

Is March 1st the first day of spring?

Yes, if you’re using the meteorological definition. The Met Office officially begins tracking spring on 1 March, and it ends on 31 May—a fixed 92-day window. This system serves practical purposes: it lets forecasters and climate researchers work with consistent date ranges year after year.

Meteorological spring explained

The Met Office (UK’s official meteorological authority) designed its seasonal system around the temperature cycle. Spring months (March–May) show a clear warming trend across the UK, making them a natural grouping. The Royal Meteorological Society explains that fixed boundaries eliminate the drift that astronomical dates experience due to leap years and orbital variations.

Why fixed dates matter

Fixed seasonal boundaries let you compare March 2026 directly with March 2025 or 2015—no adjustment needed for calendar quirks. For agriculture, retail planning, and public health tracking, that consistency is essential. The Country Living source notes that the Met Office acknowledges “spring can start at different times, depending on who you ask,” but its own standard remains the 1 March–31 May window.

Is there an actual date for the start of spring UK?

The UK has no single “official” start date for spring because two legitimate systems operate simultaneously. Both are grounded in science, but they measure different things.

Astronomical variability

Astronomical spring shifts annually because the Earth’s orbit around the sun doesn’t align perfectly with our calendar. The National Physical Laboratory provides precise dates: the 2026 vernal equinox occurs on 20 March. In other years, it might fall on 19 or 21 March. The Royal Meteorological Society notes that leap years cause these one-to-two-day variations, which ripple through the entire astronomical season schedule.

No single fixed date

The practical reality is that “spring” in the UK spans roughly 19 days differently depending on which system you consult. The Remitly Blog (cultural explainer) frames it clearly: “One date is based on the calendar months, while the other depends on the Earth’s position in relation to the sun.” Both are correct within their own frameworks.

What are the dates of the 4 seasons in the UK?

Here’s how both systems break down the UK year. The two definitions rarely align perfectly, and the gap between them shifts slightly each season.

The implication: the two systems agree on which months belong to which season for only part of the year, creating a persistent mismatch that planners and forecasters must navigate.

Meteorological seasons

Astronomical seasons (2026)

February or March: when does spring really begin?

Neither February nor any date other than March serves as an official scientific start for spring in the UK. Some traditional calendars—such as the Celtic seasonal markers—place Imbolc around 1 February, but these lack endorsement from the Met Office or National Physical Laboratory.

Why February gets mentioned

In nearby Ireland, cultural calendars sometimes group February with spring, but the UK’s primary meteorological and astronomical institutions stick to March. The Met Office is unambiguous: meteorological spring begins 1 March. The National Physical Laboratory confirms the astronomical spring date is tied to the vernal equinox, which falls in March—not February. Some media outlets in the UK do occasionally reference February as the start of spring based on traditional or cultural calendars, but these are secondary to the official scientific definitions used by weather services.

“Spring can start at different times, depending on who you ask.”

— Met Office (UK National Weather Service)

“Meteorological spring starts on March 1, while astronomical spring begins this year on 20 March.”

— Country Living (citing Met Office data)

What is the UK’s coldest month?

January holds the record as the UK’s coldest month on average. This fits the logic of the meteorological calendar: winter (December–February) has fully settled in by January, and spring warmth hasn’t yet arrived to lift temperatures. For those curious about the UK’s seasons, Is Ireland part of the UK explains when spring officially begins.

Winter context

January’s chill explains why meteorological winter runs through the end of February rather than stopping at the winter solstice. The Royal Meteorological Society notes that astronomical winter (defined by the solstice) doesn’t match the coldest part of the UK’s temperature cycle as neatly as the fixed December–February window does.

Temperature data

UK average temperatures typically bottom out in January before gradually climbing through February and March. The Met Office climate records show that March—while technically still winter under some traditional systems—already shows measurable warming. That’s precisely why meteorologists group March with April and May: the three months share a coherent warming trajectory.

Related reading: Met Office on when spring starts · Meteorological vs astronomical seasons explained

While meteorological spring kicks off on 1 March per the Met Office, the first day of spring 2026 falls precisely on 20 March at 14:46 UTC.

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