Spring Equinox 2018: when is the first day of UK Spring? And what does it actually mean?

Fiona Simpson

Britons will wake to brighter mornings and no longer face trekking home in the dark as today marks the beginning of Spring.

The Vernal Equinox falls today, marking the astronomical beginning of spring, bringing with it longer days, new blooms and the promise of some sunshine.

It follows the spring equilux on 18 March - during which day and night lasted an equal amount of time.

But what exactly is an equinox and what does it mean?

What is an equinox?

The equinox in the Northern Hemisphere occurs twice a year around March 20 (the spring equinox) and around September 22 (the autumn equinox).

They occur between the summer and winter solstices marking the point the sun crosses the equator's path.

It is then positioned exactly above the equator between the Northern and Southern Hemisphere.

According to the Met Office, the spring equinox marks the beginning of 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').

What is an equilux?

The equilux is when day and night are equal and occurs a few days before the spring equinox, and a few days after the autumn equinox.

This is different to an equinox. During an equinox the length of day and night are only nearly equal because the sun appears as a disk in the sky.

Due to the way the sun's light is refracted by the Earth's atmosphere as it rises on March 20 people will enjoy 10 extra minutes of daylight (12 hours 10 minutes).

During an equilux daylight lasts 12 hours exactly.