Autumn Equinox: What is it and what can we expect to see in the West Country?

By weather presenter: Charlie Powell

Today marks the Autumn Equinox, but it might not be exactly how we've come to describe it over the years...

The equinox is a specific point in time when the centre of the Sun (as viewed from Earth) crosses the Earth's equator. The length of day for virtually all locations on Earth is slightly longer than 12 hours, and the length of night slightly shorter than 12 hours.

Today that time was 7.50 am.

For as long as I can remember it has always been the time of year when day and night were of equal length, but that day occurs later this week and is called the "Equilux".

Arriving after the Autumn Equinox (and before the Spring Equinox), the precise day of the equilux is strongly dependent on location. The difference is because the sun appears as a disk in the sky, and the top half rises above the horizon before the centre.

As well as this sunlight is refracted, or bent, by the Earth's atmosphere. The sun therefore appears to rise before its centre reaches the horizon, giving more daylight than you might expect. This year's Autumn Equilux for the West Country falls on the 26th September.

Regardless of this we might not see that much sunlight this week as the weather is also very autumnal!

Low pressure is in charge for the next few days bringing spells of rain, strong winds and lower temperatures than we saw last week.

Read the full weather forecast for the West Country here.