Aguide 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.
三月的昼夜平分点表明此刻太阳正穿过天界赤道的时刻 - 这是一条在地球赤道上空的从南到北的虚线。这发生在每年的3月19日、20日或21日。
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.