Spring starts this week in one sense, but did you know there are actually two starts to the new season?

On Friday, we welcome the arrival of meteorological spring which annually arrives on March 1st in the Northern Hemisphere. Running from March to May.

Meanwhile, astronomical spring does not begin until the Vernal Equinox which changes slightly each year. This year it falls on March 20th.

To make matters simpler for meteorologists, it is easier to split the year into four neat quarters each three months at a time. In the UK and Ireland this is easy to do as our weather systems generally fit into four distinct patterns.

In other locations this is not possible, in the far-east for example monsoon seasons mean there are only three recognisable seasons while polar regions only see two.

Astronomical spring is based on the position of Earth in its orbit of the sun. Due to the tilt of the planet’s rotation around its axis we see solstices and equinoxes guiding the seasons.