When is the seaside at its very best? In the darkest days of winter

<span>Photograph: tirc83/Getty Images</span>
Photograph: tirc83/Getty Images

Once my work is done, and as long as the winds aren’t whipping up the valley, I head into Aberystwyth to dip into the sea. Some days I try to swim far; others I lie on my back and watch the clouds. Then I wander up to the Prom Diner and, depending on the time, order a cortado, an ice-cream or, if the day lends itself to it, a beer. I find a seat facing the sea and bask in all of it. This is a very good life.

But I cannot stay smug, because the sea has other ideas. Aberystwyth’s beaches, like those of Borth and Aberdyfi to the north, are storm beaches, which move with the sea’s weather and moods. At this time of year, they shift daily – sometimes even more often. The largely slate shingle beach that holiday folk know from summer is gone and replaced with sand.

When I say it has gone, that is not strictly true: the shingle has now breached the sea wall and is mostly on the promenade around the diner, with a smattering found even on the highest parts, around the college and the castle. Within the first week of this happening, the diner boards up its ice-cream hatch. There is another week or so of coffee, then the sea hurls up a little more shingle – enough for paw and footprints to register. The shingle pools around the planters and the base of the now-closed diner.

By Christmas last year, the winter storms had added such a dense layer that the council used a mini-digger to create narrow paths; the shingle piled into mounds that children loved to run up and down. Each day, the sea would throw up new finds for the new beach: a whole trunk of a tree; a boulder so impossibly large that it was hard to fathom how it had been moved, placed in such a pleasing position that people start using it as a seat. Then, just as quickly as it arrived, it was taken back.

Each day, the sea would throw up new finds for the new beach: a whole trunk of a tree; an impossibly large boulder

As with all shingle beaches, the sea loves to grade the pebbles, so that down on the “old” beach the largest are gathering by the sea wall. Around them, red seaweeds cluster like feather boas; in the middle, smaller pebbles are surrounded by haloes of sand, making constellations across the vast galaxy of the finest-grade shingle. There is a wonderful Black Country word for the smallest of shingle, bibble, which is smaller than a pebble, but larger than a grain of sand. One day, the sea will take all this, dump it on to the promenade and shape the beach into the smoothest sand.

In our first winter here, I couldn’t quite believe this transformation, or the accepting nature of the local people, who shrugged and said that, a week before the return of holidayers in spring, the council would sweep all the shingle back on to the beach, the diner would reopen and no one would be any the wiser.

It feels as if I am giving away secrets by telling you all this, but I love this off-duty seaside. All the naysayers told us the winters would be depressing, the stormy seas too entangled with our moods. But I like the change. Before the afternoon is lost to the darkness, I cycle down as many days as I can to say hello to the sea. If she is calm, I dip into her for as long as I can bear. Rarely am I alone: there is always someone just getting into or out of the sea, plus a line of people standing on the shingle prom, watching the starlings murmur against the setting sun. I love this worship to the thing that defines this town.

• Alys Fowler is a gardener and freelance writer