When Does Spring Start 2026? Date, Time & UK Facts

Spring’s arrival isn’t straightforward in the UK — two official dates set the season’s boundaries nearly three weeks apart. The real question isn’t just which one to circle on your calendar, but why both definitions matter and who uses which one.

Astronomical Start: March 20, 2026 ·
UTC Time: 14:46 ·
UK Confirmation: March 20 (BBC/Met) ·
Meteorological Start: March 1 ·
Equinox Type: Vernal

What is the first full day of spring in 2026?

The astronomical start of spring 2026 falls on Friday, March 20. This is when the vernal equinox occurs in the Northern Hemisphere — the moment the Earth’s axis is neither tilted towards nor away from the Sun, creating roughly equal day and night lengths (Royal Museums Greenwich).

Astronomical equinox details

From the equinox forward, days grow progressively longer than nights — a shift many people notice in their morning and evening routines. The equinox isn’t a full-day event but an exact moment, and in 2026 it occurs at 14:46 UTC on March 20.

Global time variations

• 14:46 UTC on March 20 = afternoon in Western Europe
• Same moment = March 21 local time in East Asia and Oceania
• Same moment = earlier on March 20 for the Americas

The exact UTC timing means local dates vary by timezone. This is why sources sometimes disagree on the “first day of spring” — they’re often citing the same astronomical event but different local calendar dates for it.

What date does spring start in the UK in 2026?

In the UK, spring arrives on two different dates depending on which definition you follow. The Met Office — the UK’s national weather service — states that “spring can start at different times, depending on who you ask.” For the astronomical calendar, it’s March 20. For meteorologists, spring has already begun on March 1.

UK meteorological vs astronomical

“Looking at the astronomical calendar, the first day of spring is 20th March. For meteorologists, spring starts on 1st March and runs until 31st May.”

— Met Office (UK national weather service)

The meteorological definition divides the year into four neat three-month blocks based on the annual temperature cycle: spring is always March, April, May. This consistency makes it practical for climate monitoring and forecasting.

Met Office perspective

For the UK’s national weather service, March 1 marks the start of spring because it’s a fixed date that doesn’t shift. The astronomical equinox can fall on March 19, 20, or 21 depending on the year, which complicates consistent record-keeping.

Is March 21 always the first day of spring?

No — March 21 is a common assumption, but the vernal equinox typically falls on March 20 or 21 in the Northern Hemisphere. It has even occurred on March 19 in certain years, including 2024. The date shifts because the Earth’s orbit takes roughly 365.25 days, which doesn’t align perfectly with the Gregorian calendar.

Historical variations

• 2024: March 19 (recent outlier year)
• 2025: March 20
• 2026: March 20
• 2027: Likely March 20 or 21

Leap years help correct the drift, but a full correction requires centuries. The pattern repeats over a 28-year cycle known as the Julian cycle for most calendar years, though exceptions exist due to century rules in the Gregorian calendar.

2026 specifics

Because leap years only partially correct the mismatch between Earth’s orbital period and the calendar year, equinox and solstice dates shift by a day or two over decades. The National Physical Laboratory confirms that “because of leap years, the dates of equinoxes and solstices can shift by a day or two over time.”

What time does spring start 2026?

The vernal equinox that marks astronomical spring’s start occurs at 14:46 UTC on March 20, 2026. This precise moment — not a full day — is when the Sun crosses the celestial equator, moving from the Southern Hemisphere to the Northern Hemisphere in the sky.

Exact UTC and local times

For most practical purposes, the date matters more than the exact minute. The equinox moment is a fraction of a second; its effects on daylight accumulate gradually over subsequent weeks.

Sunrise sunset context

• On the equinox, sunrise ≈ 6:00 AM and sunset ≈ 6:00 PM locally (roughly — exact times vary by longitude)
• The Sun rises due east and sets due west on this day everywhere on Earth
• From the equinox forward, sunsets grow later faster than sunrises advance

This symmetry of day and night is what gives the word “equinox” its meaning: “equal night.” The Royal Museums Greenwich notes that on the equinox, “day and night are approximately equal in length.”

What is meteorological spring?

Meteorological spring is the simpler, fixed-calendar alternative to astronomical spring. It always begins on March 1 and ends on May 31, making it exactly three months — March, April, May. This system exists because the astronomical definition, tied to Earth’s orbit, produces variable dates that complicate consistent weather record-keeping.

Definition and dates

“Meteorological spring is based on the annual temperature cycle and divides the year into four three-month seasons.”

— Met Office (UK national weather service)

The system uses full calendar months for practical reasons: March is always in spring, June is always in summer, and so on. This consistency allows scientists, businesses, and planners to compare identical date ranges across years without adjusting for variable astronomical boundaries.

Differences from astronomical

• Meteorological: Fixed dates every year (March 1 – May 31)
• Astronomical: Variable dates (March 19–21 to June 20–22)
• Meteorological seasons make year-over-year climate comparisons straightforward

Remitly confirms that “meteorological seasons remain fixed every year because they are based on full calendar months.” The key difference is predictability versus precision. For climate science, comparing March 2025 to March 2026 is meaningful only if both cover exactly the same calendar dates.

The National Physical Laboratory confirms all four seasonal boundary dates for 2026 in the UK. These astronomical markers — equinoxes and solstices — repeat every tropical year of 365 days, 5 hours, 49 minutes, with slight date shifts due to the imperfect alignment between Earth’s orbit and the calendar.

Confirmed facts vs uncertainties

What experts say

“Looking at the astronomical calendar, the first day of spring is 20th March. For meteorologists, spring starts on 1st March and runs until 31st May.”

— Met Office (UK national weather service)

“Neither is ‘wrong’—they simply serve different purposes. However, if you are looking for the moment the days truly start to dominate the nights, the astronomical equinox is the date to mark.”

— Remitly (financial services and cultural information provider)

“The astronomical definition is deeply rooted in the natural markers many people associate with spring — longer days, brighter mornings and the first signs of seasonal growth.”

— Met Office (UK national weather service)

The pattern is clear: meteorological spring serves science and record-keeping; astronomical spring serves those who want to mark the Earth’s actual position in its orbit. The Met Office acknowledges both without declaring one superior.

The takeaway

For those planning outdoor events, gardening schedules, or simply wanting to celebrate the season’s arrival, the choice is yours: mark March 1 (meteorological) or March 20 (astronomical). The Met Office, BBC Weather, and Royal Museums Greenwich all communicate the astronomical date for public audiences, while climate scientists and weather forecasters rely on March 1 for data consistency. If you’re after a specific moment tied to Earth’s orbit, wait until 14:46 UTC on March 20. If you want identical spring date ranges for comparing seasonal weather across years, March 1 is your anchor.