There are two equinoxes which happen each year, with one taking place in the spring season and another taking place in the autumn season.
But what are each of these equinoxes, what do they signify and when do each of them happen in the UK?
Here’s what you need to know.
What does the term equinox mean?
The term ‘equinox’ derives its name from the Latin name ‘eqi’, which means ‘equal’, and ‘nox’, which means ‘night’.
There are two equinoxes each year, in March and September, according to the astronomical calendar - both are when the day and night are approximately 12 hours each everywhere on Earth.
When is the spring equinox 2022 and the autumn equinox 2022?
This year the spring equinox occured on Sunday 20 March. It marked the moment when the sun crosses the earth’s equator, and day and night become equal lengths of time.
The spring equinox signifies the moment when winter finishes and spring starts, for the Northern Hemisphere.
The autumn equinox marks the start of autumn, and this year will fall on Friday 23 September.
It signifies the moment when summer ends and autumn starts, for the Northern Hemisphere.
Astronomical and Meteorological spring and autumn
According to the Met Office, “Astronomical seasons refer to the position of Earth’s orbit in relation to the Sun, considering equinoxes and solstices.
“This is due to the 23.5 degrees of tilt of the Earth’s rotational axis concerning its orbit around the Sun.
“Since the seasons vary in length, the start date of a new season can fall on different days each year.”
However, astronomical spring and autumn depends on the date of the spring equinox and the autumn equinox respectively.
There’s also meteorological spring and autumn, which differs in definition from astronomical spring and autumn.
The Met Office explains that “Meteorological seasons are instead based on the annual temperature cycle and measure the meteorological state, as well as coinciding with the calendar to determine a clear transition between the seasons.”
The meteorological seasons are split into four periods made up of three months each, in order to coincide with the Gregorian calendar, “making it easier for meteorological observing and forecasting to compare seasonal and monthly statistics,” adds the Met Office.
“By the meteorological calendar, spring will always start on 1 March; ending on 31 May and autumn will always start on 1 September; ending on 30 November.”
How do people celebrate the autumn equinox?
The celebration of the autumn equinox, known by several names, including Harvest Home, Mabon or simply the equinox, is often described as the Pagan Thanksgiving.
The festival is held to thank Mother Earth for providing a good harvest to last through winter, and in line with this animals are traditionally slaughtered and preserved at the equinox in order to provide enough food for the coldest months of the year which follow autumn.
Today, however, animal slaughters do not take place and many pagan groups instead choose to have a huge feast to mark the autumn equinox with their family and friends using seasonal foods such as apples, grapes, root vegetables and other seasonal products.
How do people celebrate the spring equinox?
Ostara is a pagan celebration of the spring equinox, which has been both observed and celebrated for a long time in many areas around the globe.
Ostara, also known as Ēostre, is the Germanic goddess of spring and dawn. On the old Germanic calendar, the equivalent month to April was called “Ōstarmānod”, also known as Easter-month.
Gatherings take place to celebrate spring equinox around the world. At El Castillo in Mexico, which is the site of the Mayan ruins of Chichen Itza, people watch the sun create snake-like shadows on the pyramid steps, with similar events taking place at Mayan temples across central America.
What are the first signs of autumn?
Autumn is the transition season between summer and winter, best noticed by the colour change in leaves and the harvest, according to the Met Office.
The most noticeable sign of autumn in the UK is the changing colours of the leaves. As a result of the falling temperatures in autumn, the chemical in the leaves that makes them green, called chlorophyll, begins to break down while other chemicals, including carotene, remain to give the leaves their yellow, red and brown colours.
What is the weather usually like in autumn?
Autumn is normally associated with dropping temperatures and the nights drawing in as winter approaches.
The Met Office said: “In the UK autumn can often bring unsettled weather and towards the latter part of the season can often bring stormy conditions with strong gales due to Atlantic depressions moving over the UK.”
What are the first signs of spring?
You may define spring as the time when the nights get lighter and longer, or perhaps less chilly, with the Met Office explaining it as, “the transition season between winter and summer during which we see days getting longer, temperatures warming and plants blossoming in time for summer.
What is the weather usually like in spring?
Although the weather can be temperamental during the period of spring, it’s often warmer and drier than the winter and autumn months.
The Met Office explains that it is “often calm and dry due to the Atlantic losing heat during autumn and winter, leading to less heat and moisture being transferred to the atmosphere.”
The sun is high in the sky during springtime, which means temperatures can rise in the day, but then stay cool at night due to the “moderating effect of the ocean temperature.”
The Temperatures seen in the UK during spring are “largely influenced by latitude, with northern parts of the UK such as Scotland seeing cooler temperatures compared to the lower latitudes and the southern UK experiencing warmer temperatures,” explains the Met Office.