Is the autumn equinox the start of a new season?

There are just a handful of astronomical events that non-specialists like me know of, and one of them will be upon us very soon: the autumn equinox. On 22 September 2021, day and night will be equal in length across the whole world. How so? Well, normally the sun illuminates one of our world’s two hemispheres – the southern and the northern – more than the other, making day and night of different lengths in each. However, at an equinox it illuminates them equally at the moment that the plane of the equator passes through the centre of the sun’s disc. The exact timing of the event this year is 8:21 p.m. BST, so set your timepieces now.

The autumn equinox raises the knotty question of when precisely autumn begins. And I won’t reply with that most irritating passive-aggressive phrase ‘How long is a piece of string?’ As the Royal Observatory at Greenwich explains, it all depends on whether you take an astronomical, a meteorological or a phenological approach. Astronomically speaking, it’s the equinoxes and solstices that determine the seasons; thus, autumn might indeed ‘begin’ with the autumn equinox. However, the date and time of the equinoxes varies slightly, which arguably prevents them being a firm yardstick to calibrate the seasons by. The weather people take a second approach by applying a sort of Ockham’s razor and simply carve the year sausage into four quarters of three months. They take the easy-peasy route and make autumn begin on 1 September and end on 30 November. Doing so makes it easier to compare seasonal statistics year on year.

The third approach could be parodied as a sort of hippy-dippy ‘if you feel it’s autumn, then it is autumn, man’. More soberly, phenology studies cyclic and seasonal events in the plant and animal kingdoms such as animal migration or leaf fall – the second of which, of course, gives us the venerable word for autumn, fall, a sixteenth-century shortening of the earlier fall of the leaf. We Brits went on using fall throughout the seventeenth century. For example, the eminent botanist and diarist John Evelyn [1620–1706] in his pioneering work on forestry Silva (1664) described the English oak (Quercus robur) as ‘distinguished by its fulness of leaves, which tarnish, and becoming yellow at the fall, do commonly clothe it all the winter.’ Evelyn is describing here marcescent leaves, namely, leaves that though brown do not drop in winter. You will see them on beech hedges everywhere. And if one day – never say never – you need an adjective with the meaning  ‘relating to or characteristic of oak trees’, that Latin word for oak, quercus, bountifully provides you with quercine. After Evelyn’s time, autumn seriously curtailed the use of fall on these shores, though it was recorded as still current in several rural areas of England in the twentieth century according to the Survey of English Dialects.

The autumn equinox has a twin earlier in the year, the spring or vernal equinox, which occurs around the 20th of March. Equinox is a word that singularly fails to do what it says on the tin. Its Latin ancestor aequinoctium means something like ‘equal night’, combining as it does aequus (‘equal’) and nox, noctis (‘night’) so the day part of ‘equal day and night’ is omitted. The homegrown German word for equinox, in contrast, sets out its stall very clearly: die Tagundnachtgleiche, literally ‘the dayandnightsame’. Danish takes a similar tack with det jævndøgn, literally ‘the even 24-hour day’, and Middle English even borrowed from early Scandinavian the word evenlength (geuelengðhe), while Old English had efen-niht and variants (‘even night’), which sounds very much like a calque on the Latin aequinoctium already discussed. The Romance languages, as you might expect, have variations on the Latin, e.g., French équinoxe, Spanish equinoccio.

Going back to the phenological signs of the seasons, the eddies of fallen leaves stirred by the breeze tell me that, subjectively, autumn is hovering in the wings. It could be argued that there is yet a fourth starting pistol for autumn: the last weekend in October, that Saturday evening/Sunday morning over which British Summer Time ends and one ‘gains’ an hour. (Remember the helpful adage: ‘Spring forward, fall back.’)

October is also the proper month in which to savour the exquisite, musical melancholy of W.B. Yeats’ ‘The Wild Swans at Coole.’

Below is a taster.

Tip: if you read the whole poem to yourself, read it v-e-r-y s-l-o-w-l-y. Most of the recordings I’ve found online are much too fast.

The trees are in their autumn beauty,
The woodland paths are dry,
Under the October twilight the water
Mirrors a still sky;
Upon the brimming water among the stones
Are nine-and-fifty swans.

By Jeremy Butterfield
Jeremy Butterfield is the former Editor-in-Chief of Collins Dictionaries, and editor of the fourth, revised edition of Fowler’s Dictionary of Modern English Usage.

All opinions expressed on this blog are those of the individual writers, and do not necessarily reflect the opinions or policies of Collins, or its parent company, HarperCollins.