Autumn Equinox 2022: the science behind the changing seasons

When leaves begin to fall, temperatures drop and days become shorter, it can only mean autumn is here - and brings with it home comforts, bronzed woodland hues and a pumpkin or two.

For many, autumn is enjoyable because of its festivals and the sense that "life starts all over again when it gets crisp in the fall", if you're of the same opinion as F. Scott Fitzgerald.

According to the astronomical calendar, the seasonal transition occurs on 23 September, the date of the Autumn equinox. However under the meteorological definition, which is based on the Gregorian calendar, autumn began on 1 September.

Here is everything you need to know about the changing seasons, from how the equinox works to what you can look forward to over the coming months.

Why is it called the autumn 'equinox'?

Since night and day are nearly exactly the same length – 12 hours – all over the world the event is called the equinox, which literally means 'equal night' in Latin (equi – equal, and nox – night).

In reality though, equinoxes do not have exactly 12 hours of daylight. Solstices and equinoxes mark key stages in the astronomical cycle of the earth. In a year there are two equinoxes (spring and autumn) and two solstices (summer and winter).

This year, the autumn equinox takes place 23 September.

The dates of the equinoxes and solstices aren't fixed due to the Earth's elliptical orbit of the sun. They are closest in January, and most distant in July (aphelion).

The equinox marks the change of seasons, as the balance of light shifts to make for longer days or nights. Whether that means snow storms or heat waves depends on the hemisphere.

It is also possible to see the Sun rising and setting directly in the East and West, whereas it appears off-centre at other times of year.

What happens on an equinox?

The Earth's axis always tilts at an angle of about 23.4° in relation to the ecliptic, i.e the imaginary plane created by the Earth's orbit around the Sun.

On any other day of the year, either the Northern Hemisphere or the Southern Hemisphere tilts slightly towards the Sun but on the two equinoxes, the tilt of the Earth's axis is perpendicular to the Sun's rays.

The equinox occurs at the exact moment the Sun crosses the celestial equator – the imaginary line in the sky above the Earth’s Equator – from south to north.

At this moment, the Earth's axis is neither tilted away from nor towards the Sun.

Autumn festivals around the world

With a new season comes an excuse for celebration - here's our guide to the festivals most associated with autumn around the world.

Alba White Truffle Festival, Italy

In Piedmont, the season of harvest brings thousands of visitors to the International Alba White Truffle Festival – Fiera Internazionale del Tartufo Bianco d’Alba - hoping to purchase and sample the local delicacy from local farmers.

There's music, cultural events and markets providing a feast of local food and wine, as well as the famous white truffle that grow among the poplar trees in the hills of this northern Italian region.

This year's fair is scheduled to take place in Alba, Italy, from 9 October to 5 December.

Diwali, India (but celebrated worldwide)

This festival sees fireworks, lights and feasting take place across the Hindu, Sikh, and Buddhist world, upon the new moon that falls at the end of October or early November. This year's celebration falls on Thursday, 4 November.

Oil lamp decorations burn in the streets, creating an atmospheric nighttime spectacle. In fact, the word 'Diwali' means "rows of lighted lamps" in Sanskrit, an ancient Indian language.

For Indians, this national holiday commemorates the return of Ram, the lord of virtue. It also marks the end of harvest season, so prayers of thanks are also given to Lakshmi, the Hindu goddess of wealth and prosperity.

Halloween, Ireland (but celebrated worldwide)

This is perhaps the event that put pumpkins on the cultural map: Halloween is celebrated on 31 October with traditions new and old, such as fancy dress parties, trick-or-treating, and pumpkin carving.

Though now associated with Americanisation, the traditions of Halloween are thought to have begun in Celtic Britain. The event has two rumoured origins: either as a Pagan festival celebrating the end of harvest or the Christian feast of All Hallows.

The celebration has been particularly popular with children over the last century, when many American traditions such as pumpkin carving came to Europe.

Bonfire Night, UK

In the UK, November 5 marks the day that Guido Fawkes attempted to blow up Parliament in 1605, in the famous Gunpowder Plot.

On that date, Londoners lit bonfires in celebration of the failed plot, and so in 1606 the 5th November Act was passed to ensure a public holiday in celebration of the fact.

Although bonfire night traditions have changed over the years, many people still gather for public firework displays and events such as the Lewes Bonfire, Sussex: the largest event of its kind, which sees a torch-lit parade and the burning of famous effigies.

Thanksgiving, North America

A day spent with family, close friends and a traditional North American feast. Thanksgiving, which falls on Thursday 24 November in the United States and Monday 10 October in Canada in 2022, became a holiday centered on coming together around the time of harvest and remains much the same today.

In the United States, the first feast between Plymouth colonists and Wampanoag Indians took place in 1621, while in Canada the first 'Thanksgiving' took place as early as 1578 after the Englishman Martin Frobisher returned from exploring the Northwest Passage.

Some of the most well-known Thanksgiving spectacles include the Macy parade in New York and the Canadian Football League's 'Thanksgiving Day Classic'.

In the States, the November holiday comes a day before the Black Friday sale, marking the beginning of the Christmas shopping season.

Warming recipes to indulge in this autumn

Venison pie with buttermilk mash recipe

This is a homemade pie with a difference - a comforting plate of steaming goodness, accompanied by a buttery, creamy mash. Perfect to ease you into the autumnal season and see you through the colder days, it also features chunky bacon lardons and chestnut mushrooms.

Moroccan spiced bean soup recipe

This is based on the Moroccan soup, harira, which is traditionally eaten every day throughout the month of Ramadan. Friends tell Xanthe Clay that they never get sick of it, so it’s a good recipe to scale up for future meals. It’s very adaptable: here, dried fava beans (not easily available here) have been substituted for frozen broad beans.

Roasted delicia pumpkin, feta and rye galette recipe

This galette is perfectly seasonal and savoury. When they come into season, I always buy a few and make sure I use them to their full advantage! If not, you can also use crown prince squash or another pumpkin. One of the biggest factors here that will help you to achieve a galette packed full of flavour is to taste the filling as you go and adjust the seasoning accordingly. I love chilli, garlic and herbs, so often I will add a bit more of each one to this.

Salted caramel chocolate pie recipe

If you are looking for a quick, minimal-faff but highly indulgent baked treat, this could be your answer.  This stars a no-bake cheesecake base, a layer of shop-bought salted caramel and a pillowy soft, dark chocolate moussey layer.

This article is kept updated with the latest information.