At the close of the year, it is nice to look back on its greatest hits. This year I find it comes to me in waterborne flashes. Here’s one: a sweltering day in the sea-green swell off the Jurassic Coast. A natural arch of limestone looming overhead, a pebble floor falling vertiginously away below as I strike out from shore. Water clear as glass, as air: a sensation of taking flight. And another: shin-deep in a saline sea, somewhere in the Sonoran Desert. Skin tingling; sun sinking behind the mountains; a hazy, amethyst sky.

But swimming is by no means only a summer activity. To dry off at the season’s end is to miss so much that is magical. For my fairweather friends, I find it best to introduce the idea by degrees.

Autumn, then: a wonderful time to be submerged. After its long slow bask in the sun, it’s now warmer to be in the water than out. Leaves of crimson, rust, amber and lemon-yellow swirl in your wake. At dawn, the low mist drifts across the surface like smoke.

September saw me plunging headlong into the sea from a rowing boat in bikini and flippers: brushing through forests of kelp; stalking crabs across the sea floor. October: scrambling through tangerine thickets of sea buckthorn in the dunes at Gullane off the Firth of Forth; wading through white-tipped breakers; bobbing in the company of three red-breasted mergansers.

Then, among the waterfowl, came the changing of the guard. On winter’s approach, in came the chestnut-headed wigeons and pochards, the tufted ducks with their slicked-back quiffs and walleyed stares. (A regular swimmer can mark off the months by the company they keep.) Trees grew threadbare; the landscape washed out. All the time the temperature was sinking, sinking, sinking. But if anything, the swimming was getting better.

Dive in

Bear with me. Cold water swimming has a great deal to recommend it. It is one of nature’s most bracing experiences, a shock to the body and a reset for the mind—and, as the British Medical Journal recently reported, is currently under investigation as a treatment for depression.

There is nothing so invigorating as swimming through sleet and snow and hail, or descending into water through a hole in the ice: the gasping, stinging shock of it, cold pressing in on your body from all around before, as the seconds pass, the frigid waters grow bearable, even comfortable.

“Swimming” is perhaps a misnomer for my midwinter activities. “Wallowing” would be more accurate. As the patron saint of wild swimmers Roger Deakin once wrote: “When you enter the water, something, like a metamorphosis happens. Leaving behind the land, you go through the looking glass surface and enter a new world…” Here, everything looks different because “survival, not ambition or desire, is the dominant aim.” It changes one’s perspective. It rallies the spirits.

It’s true that as you learn to push past discomfort, survival must stay foremost in your mind. The spectre of hypothermia is ever present, and her hangers-on: shivering, slurring of speech, disorientation. Open water experts recommend outdoor swimming at least once a week through the winter to maintain your tolerance. Try not to swim alone.

A strange pastime, perhaps. But perversely pleasurable. Try it some time: immerse yourself in nature.