When Does Spring Start? Meteorological vs Astronomical Dates, and the Signs You’ll Notice in the UK
Spring is often described as the season of renewal: brighter mornings, longer evenings, and the first real sense that winter is loosening its grip. Yet the simple question “when does spring start?” has more than one correct answer. The date depends on which definition you are using, and each one is designed for a different purpose.
In the UK, two main systems are commonly referenced. Meteorological spring is fixed to the calendar and is especially useful for consistent record-keeping and climate analysis. Astronomical spring is tied to the Earth’s position relative to the Sun and begins at the vernal equinox, a natural marker that many people associate with the changing light and the shift into a new season.
Understanding both definitions helps explain why spring can feel as if it arrives at different times in different years, and why the “official” start date you hear may not match what you’re experiencing outside your window.
Why the start of spring isn’t a single date
Seasons can be defined in more than one way because “spring” is used for more than one job. It can be a scientific category used to compare temperature and rainfall patterns over decades, and it can also be a description of a real-world transition driven by daylight, solar angle, and the behaviour of plants and animals.
That’s why two definitions are widely used at the same time:
Meteorological spring, which uses fixed dates and three-month blocks.
Astronomical spring, which begins at the vernal equinox and can shift slightly year to year.
Both are valid. They simply measure the season from different angles.
Meteorological spring: a fixed season from 1 March
Meteorological seasons offer a straightforward and consistent way to divide the year. In the UK, meteorological spring always begins on 1 March and ends on 31 May.
This approach divides the year into four fixed seasons, each lasting three months. The advantage is consistency: when each season is the same length every year, it becomes easier to compare long-term records and identify broader patterns in temperature, rainfall, and sunshine.
Because of that, meteorological spring is particularly useful for:
Climate monitoring and the comparison of long-term records
Long-term forecasting
Communicating typical seasonal weather conditions in a clear, repeatable framework
In practical terms, meteorological spring is often described as a bridge between winter’s cooler, more unsettled weather and the warmer, more stable conditions that summer can bring. Day-to-day weather can still vary widely, but the fixed season provides a stable reference point for analysing what is happening overall.
Astronomical spring: the vernal equinox around 20 March
Astronomical spring is defined by the Earth’s position in relation to the Sun. It begins on the vernal equinox, which falls around 20 March in the Northern Hemisphere.
The equinox is often described as the point when day and night are roughly equal in length. It marks a turning point in the year when daylight hours begin to increase more rapidly, a change many people notice in everyday life through earlier sunrises and later sunsets.
Unlike meteorological spring, the astronomical start date is not fixed. The precise timing of the equinox can shift slightly from year to year. This variation is linked to:
The Earth’s axial tilt
The slightly elliptical shape of the Earth’s orbit around the Sun
Even though the date can move a little, the astronomical definition remains closely tied to the natural cues people associate with spring: longer days, brighter mornings, and the first signs of seasonal growth.
What many people notice before any “official” start date
Calendars and equinoxes are helpful for defining seasons, but spring is also something people feel and observe. Many notice its arrival before 1 March or before the vernal equinox, because the transition is gradual and nature offers recognisable signals.
These cues don’t always line up neatly with a single day. Instead, they build over weeks as the balance of light and warmth begins to shift.
Longer daylight: one of the clearest signals
One of the most noticeable changes in spring is the gradual increase in daylight. After the vernal equinox, the balance tips more clearly toward longer days, with earlier sunrises and later sunsets.
This isn’t just a pleasant change for evening walks. Increasing daylight plays a major role in shaping plant and animal behaviour and is often linked to a boost in people’s sense of energy and wellbeing.
Rising daytime temperatures, with chilly nights still possible
As the Sun climbs higher in the sky during spring, daytime temperatures begin to rise. In many parts of the UK, afternoons become noticeably warmer as the season progresses, especially toward late April and May.
However, spring warmth can be uneven. Nights can still feel chilly, in part because the ocean remains relatively cool after winter. This contrast between warmer days and cooler nights is one reason spring can feel changeable, even when the overall trend is toward milder conditions.
Plants and wildlife: classic markers of the season
For many people, spring truly feels as if it has started when the landscape changes. Blossoming trees, the return of birdsong, and increased insect activity are among the most familiar indicators that the season is underway.
These changes are part of what scientists call phenology, the study of seasonal shifts in plants and animals. The term “vernal,” used in “vernal equinox,” comes from Latin for “bloom,” reflecting the burst of colour and life that is widely associated with this time of year.
Why spring weather can feel so variable
Spring weather is often among the most changeable of the year. The season can bring a mix of calm, dry spells and sudden shifts as the atmosphere adjusts toward summer conditions.
This variability can be one reason people disagree about whether spring has “really” arrived. A mild, sunny spell can make it feel as if winter is over, only for colder air or unsettled conditions to return shortly afterwards. The broader seasonal direction may be toward warmth and longer days, but the day-to-day experience can still swing.
Spring doesn’t arrive at the same time everywhere in the UK
The UK does not experience spring uniformly. Regional contrasts shape how the season is felt across the country.
Northern areas, including Scotland, typically remain cooler for longer.
Southern parts of the UK tend to warm up earlier.
These differences influence everything from when early blooms appear to how long frost risk lingers. What feels like settled spring weather in one region may still feel closer to late winter in another.
Can it still snow in spring?
Despite spring’s milder reputation, snow remains a possibility, especially in March. Statistically, March has a higher likelihood of snow or sleet than December. That means late cold snaps can occur even as daylight is increasing and the season is moving forward.
This is also why snow around Easter, while surprising to some, is not unusual within the UK climate. Spring’s identity as a transition season is reflected in these contrasts: brighter days and signs of growth can coincide with wintry hazards.
Average spring temperatures: how the season compares with winter
Across the 1991–2020 climate period, the long-term average UK spring temperature is 8.08°C. This figure reflects the gradual warming trend through March, April, and May, with May typically bringing the first consistently warm days of the year.
For comparison, the long-term average for UK winter is 4.09°C. The difference helps explain why spring can feel like a significant shift in comfort and daily routine, even though cold nights and occasional wintry weather can still occur.
The bigger picture: why seasons happen at all
Spring is one part of the annual cycle of seasons, shaped by the Earth’s tilt. The Earth’s axis is tilted at 23.5 degrees. As the planet orbits the Sun, different regions receive varying amounts of solar radiation at different times of year.
This changing balance of sunlight is what creates the seasons: longer days and rising temperatures in spring, followed by summer warmth, autumn cooling, and winter’s shorter days.
Seeing spring in this context helps explain not only when it begins, but why it plays such an important role in the natural world. It is the period when the balance of light shifts quickly, setting the stage for the warmer months ahead.
A practical way to think about the start of spring
If you want a clear, consistent date for planning or for comparing weather from one year to the next, meteorological spring starting on 1 March is the simplest reference. If you prefer a definition linked to the Earth–Sun relationship and the changing length of day, astronomical spring begins at the vernal equinox around 20 March.
At the same time, the lived experience of spring often arrives in stages: a little more daylight, a slightly higher Sun, warmer afternoons, and the gradual reappearance of seasonal plant and animal activity. In the UK, those signs can show up at different times depending on where you are, and they can be accompanied by the kind of changeable weather that makes spring feel like a true transition.
Key points at a glance
Meteorological spring in the UK runs from 1 March to 31 May, offering a consistent three-month season for climate records and analysis.
Astronomical spring begins at the vernal equinox around 20 March, when day and night are roughly equal and daylight begins increasing more rapidly.
Spring weather can be highly variable, with a mix of calm spells and sudden changes.
Spring arrives differently across the UK, with the south typically warming earlier than northern areas including Scotland.
Snow is still possible in spring, particularly in March, which statistically has a higher likelihood of snow or sleet than December.
The long-term average UK spring temperature (1991–2020) is 8.08°C, compared with 4.09°C for winter.