Equinox marks start of astronomical spring
- Published
The spring equinox happens on Friday 20 March, and marks the start of astronomical spring for the Northern Hemisphere.
Spring in their step - lambs play in the fading sun in Davenham, Cheshire on last year's equinox
The Earth orbits the sun once a year, and spins on its axis once every 24 hours - which gives us day and night.
But the Earth is also tilted by 23.5 degrees towards the sun during summer which is why the days are lighter for longer. Conversely it's tilted away from the sun during the winter months.
For meteorologists spring began on 1 March - meteorological seasons are divided into months to make it easier for record keeping. Picture taken in Outwell, Norfolk, during last year's equinox sunset
The equinox is the moment where the Earth is neither tilted towards or away from the sun, so the duration of daylight is theoretically the same at all points on its surface.
Hence the word equinox, which comes from two Latin words, 'equi' which means equal and 'nox' meaning night.
Last year's spring equinox also coincided with a supermoon. This was the spectacular view as it rose over over the Wrekin, Shropshire
The date of the spring equinox varies - it can happen on the 19, 20 or 21 March each year.