Spring Equinox 2019: Why is today the first day of Spring in the UK? What is the vernal equinox?

Tom Herbert

It may not feel like it with the grey skies and brisk winds we're experiencing, but as today's Google Doodle will tell you - spring is officially here.

The Spring Equinox, or the Vernal Equinox as it's more formally known, marks the astronomical start of spring when the sun passes north through the Earth's equator.

From March 20 the days will begin to get longer and the nights shorter as the Earth wakes up from its winter hibernation and Brits look forward to the promise of sunshine.

Here's all you need to know about the Vernal - or Spring - Equinox.

The Spring Equinox marks the beginning of spring (Unsplash)

When is the Spring Equinox?

The Spring Equinox falls on March 20 this year, which marks the first day of the astronomical spring. The meteorological spring fell on March 1.

The Met Office says that astronomical seasons "refer to the position of Earth's orbit in relation to the sun," whereas meteorological seasons are "based on the annual temperature cycle" to coincide with the calendar.

This year, the Spring Equinox takes place on Wednesday, March 20 at 9.58pm UK time - just four hours before the third and final supermoon of the year will take place.

The Spring Equinox always falls on one of three days towards the end of March.

Spring is nearly here (Unsplash)

What is the Spring Equinox?

An equinox is a phenomenon which only happens twice a year - once during the Spring Equinox and once during the Autumn Equinox.

In the Northern Hemisphere the Spring Equinox happens around March 20, marking the end of winter and the beginning of spring.

The Autumn Equinox occurs around September 23 in the Northern Hemisphere and marks the beginning of autumn.

An equinox happens between the summer and winter solstices, marking the point when the sun positions itself exactly above the equator before crossing through it.

According to the Met Office, the spring equinox marks the beginning of astronomical spring and from this day forward the day is longer than the night.

The autumn equinox marks the start of autumn as the night becomes longer than the day.

What does equinox mean?

During the equinox, day and night will be around the same length.

The name comes from the Latin word equi (meaning 'equal') and nox (meaning 'night').