A guide to what the spring equinox means and how you can make the most of it.
When did spring start then?
The astronomical spring in the Northern Hemisphere began on Monday, March 20 and will end on Wednesday, June 21.
The spring (vernal) equinox in the Northern Hemisphere is also known as the March equinox. It's called the "autumnal (fall) equinox" in the Southern Hemisphere.
The March equinox marks the moment the Sun crosses the celestial equator – the imaginary line in the sky above the Earth’s equator – from south to north. This happens on March 19, 20 or 21 every year.
Why is it called the spring 'equinox'?
Since night and day are nearly exactly the same length – 12 hours – all over the world the event is called the equinox, which in Latin, literally means 'equal night' (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).
The dates of the equinoxes and solstices aren't fixed due to the Earth's elliptical orbit of the sun. The Earth's orbit around the sun means that in early January, the sun is closest (known as perihelion) and in early July it is most distant (aphelion).
We use the equinox to mark the change of seasons, as the balance of light shifts to make for longer days or nights. It usually means that it's time to hunker down for colder seasons, or time to rise and shine for warmer ones.
You may also notice that on the equinox, the sun rises directly in the east and sets directly in the west, whereas at other times in the year, it appears off-centre if you're facing those directions.
What happens on an equinox?
The Earth's axis always tilts at an angle of about 23.5° 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 a little towards the Sun but on the two equinoxes, the tilt of the Earth's axis is perpendicular to the Sun's rays.
The equinox happens at exactly the same time around the world
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. In 2017, this happens at 10.20am UTC (GMT).
The first day of spring 2017 sees the latest in a series of Google Doodles.
After all, what better way is there to mark the beginning of the season than with nature springing back to life?
Celebrating new Beginnings
The March equinox has long been celebrated as a time of rebirth in the Northern Hemisphere. Many cultures celebrate spring festivals and holidays around the March equinox, like Easter and Passover.
Japan's cherry blossom
In Japan, as spring approaches, the arrival of cherry blossom (Sakura) is hotly anticipated as the nation turning a shade of pink with the arrival.
Months before they arrive, retailers switch into sakura mode, Danielle Demetriou writes.
The countdown excitement is heightened further by the televised Cherry Blossom Forecast which offers a petal-by-petal analysis of the advance of the blooms – known as the cherry blossom front – as they sweep from the south to the north of the archipelago.
Nowruz is the name of the Iranian New Year, also known as the Persian New Year, which is celebrated worldwide, along with some other ethno-linguistic groups, as the beginning of the New Year.
In Farsi, Nowruz means "New Day". It is a festival that has roots in Zoroastrianism and has been celebrated for over 3,000 years in Western Asia, Central Asia, the Caucasus, the Black Sea Basin and the Balkans.
Before the collapse of the Soviet Union, Iran was the only country that officially observed the ceremonies of Nowruz.
When the Caucasian and Central Asian countries gained independence from the Soviets however, they also declared Nowruz as a national holiday.
Nowruz marks the first day of the first month (Farvardin) in the Iranian calendar and is often celebrated at the exact moment of the vernal equinox, when the days start getting longer, and the celebrations can continue for up to two weeks.
Perhaps the most enduring image of Nowruz is gathering together with friends and family around a bonfire. People also like to decorate with springtime flowers, like the hyacinths and tulips in today’s Doodle.
The colourful Hindu festival of Holi is celebrated as the vernal equinox approaches.
The ancient religious festival has become popular across the world, including celebrations across the UK, though it is mainly observed in India and Nepal.
The celebrations begin with a bonfire the previous evening where revellers sing and dance.
The following day involves participants throwing colour over each other, either with dry powder and water or coloured water-filled balloons.
The festival signifies the victory of good over evil with the onset of spring and the end of winter.
Easter also has associations with the Spring break enjoyed by college students in the US, and has connotations of beach holidays and raucous parties.
The 2012 film Spring Breakers starring Selena Gomez, Vanessa Hudgens and James Franco takes this to an extreme as it follows James Franco’s gangster rapper as he takes four bikini-clad young women on a tour of Florida.
The Easter Bunny
It is thought that the Ango-Saxon Goddess of Spring, Eostre, had a hare as her companion, which symbolised fertility and rebirth.
It’s hardly surprising that rabbits and hares have become associated with fertility as they are both prolific breeders and give birth to large litters in early spring.
The legend of the Easter Bunny is thought to have originated among German Lutherans, where the ‘Easter Hare’ judged whether children had been good or bad in the run-up to Easter.
Over time it has become incorporated into Christian celebrations and became popular in Britain during the 19th century.
Many children believe that the Easter Bunny lays and hides baskets of coloured eggs, sweets and sometimes toys in their homes or around the garden the night before Easter Sunday – much like Father Christmas delivering gifts on Christmas Eve.
This has given rise to the tradition of the Easter egg hunt which is still popular among children today.
Spring Lamb recipes
A Spanish roast with a spring-like twist of lemony herb relish and warmed peas
Caramelised sweetbreads contrast with fresh ricotta and a minty, citrus salad.
Plump lamb chops cured in garlic, ginger and chilli are smoked over green tea and wood chips before grilling. Delicious with a spicy Korean miso.
A simple and quick dish of pan-fried lamb teamed with warm broad beans and fresh mint.
A rich and vibrant stew of chunky lamb with red peppers and coriander.
A beautiful stuffed roast saddle, served with a saffron jus.