The UK has been hit by a record-breaking heatwave this summer, with temperatures soaring above 40C for the first time.
Although it looks like there’s plenty more hot weather to come, now that we are past the summer solstice the days are gradually shortening and the leaves will eventually fall from the trees.
This can only mean one thing: autumn is coming. Here’s everything you need to know about the dates of the fall season in the UK, and what the autumnal equinox means.
When does autumn 2022 start?
Autumn’s first day can fall on two different dates, depending on whether you use the meteorological or the astronomical definition.
The meteorological system is the simpler of the two. It splits the year into four seasons of three full months each based on the Gregorian calendar, which makes it easier to compare seasonal and monthly statistics.
So every year, autumn lasts from 1 September until 30 November, with winter then kicking off at the beginning of December.
Under the meteorological calendar, spring then always encompasses March to May, with summer lasting from the start of June until the end of August.
The astronomical season isn’t quite as straightforward, because it is based on the position of the autumnal equinox, which comes later in the month and doesn’t always fall on the same date.
This results in autumn having a different start date than under the meteorological system. This year’s autumnal equinox is on Friday 23 September – it can be any position between 22nd and 24th of the month.
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According to this system, autumn gives way to winter on the date of the winter solstice, which this year falls on Wednesday 21 December.
Astronomically speaking, this year’s summer began on Tuesday 21 June, the date of the summer solstice.
What does the autumnal equinox mean?
Equinoxes get their name from the Latin for “equal night”, and denote the only two points in the year when the equator is the closest part of Earth to the sun.
In theory, this means that everywhere on the planet should get 12 hours of daylight and darkness on those days, although this is complicated slightly by the Earth’s atmosphere affecting the way we see sunlight.
For six months each of the year, either the northern or southern hemisphere is pointing slightly towards the sun, bringing the warmer temperatures of spring and summer.
The autumnal and spring equinoxes mark the point when the two hemispheres swap over, while the summer and winter solstices denote the sun reaching its most northerly and southerly points.
