The weather might be chilly but the mornings are getting lighter, meaning that spring has arrived.
The clocks are set to change on Sunday 26 March – ushering in longer days. However, this does not mark the start of spring.
Spring actually has two different start dates in the UK, depending on how you calculate it – here’s how it all works, and what you need to know about the vernal equinox.
When is spring 2023?
What is considered the first day of spring depends on whether you are using the meteorological or astronomical definition of the seasons.
The meteorological is the simpler of the two, because it splits the year into four seasons of three full months each based on the Gregorian calendar, making it easier to compare seasonal and monthly statistics.
This means that every year spring begins on 1 March and continues through April until 31 May, with summer then starting on 1 June.
The astronomical season is less straightforward as it depends on the date of the spring equinox, which means the date comes later and can vary slightly from year to year.
When is the spring equinox?
In 2023, the spring (also known as vernal) equinox falls on Monday 20 March at 9.24pm. This is the most common date for the phenomenon by some distance, although it can fall any time between the 19th and 21st of the month.
The astronomical spring will then last until the summer solstice, which in 2023 is on Wednesday 21 June.
What is the vernal equinox?
Equinoxes get their name from the Latin for “equal night”, and mark the only two points in the year when the equator is the closest part of Earth to the sun, with both the northern and southern hemispheres sharing sunlight equally.
In theory, this means that everywhere on the planet should get 12 hours of daylight and darkness on those days, although this is complicated slightly by the Earth’s atmosphere affecting the way we see sunlight.
For six months each of the year, either the northern or southern hemisphere is pointing slightly more towards the sun, bringing the warmer temperatures of spring and summer.
The autumnal and spring equinoxes mark the point when the two hemispheres swap over, while the summer and winter solstices denote the sun reaching its most northerly and southerly points.
“Vernal” simply means something related to spring, so the names can be used interchangebly.
What are the traditions behind the equinox?
While the solstices are more widely understood to be rooted in ritualistic tradition and celebration, the equinoxes carry meaning for many people too.
Early civilisations found the spring equinox to be a reliable way to keep track of the seasons, with cultures today paying tribute as their ancestors used to.
In the UK, Stonehenge is the most famous meeting point for druids and pagans, who traditionally gather annually (when pandemics allow) to watch dawn break with dancing and song.
Gatherings happen around the world; at El Castillo in Mexico, the site of the Mayan ruins of Chichen Itza, people watch the sun create snake-like shadows on the pyramid steps, and similar events take place at Mayan temples across central America.