It started with a text, when it was still hot. Did we fancy doing morning swims at the lido, perhaps once a week? I re-named the WhatsApp group: “swim club”.

It’s been three months now, and the mornings are milkier. On Wednesdays we cycle through the backstreets, still quiet before the school runs begin. Sometimes a bin lorry, sometimes a bus. As the weeks have passed we have developed our uniforms: sweat pants, roomy dresses, thick socks and Birkenstocks. No goggles; we swim like old ladies here. When there aren’t enough staff to open the lane that accommodates us - with no speed attached, simply enough room to swim three abreast and talk while we’re doing it - we join the lido elders in complaining, and duck under the plastic ropes anyway.

The lido isn’t heated. If it’s cold outside, which it hasn’t been often, the temperature of the water shuffles down too. The numbers are written on a white board haunted by the ghosts of earlier days. Fourteen degrees is the teetering point: above it is fine, below is cold. After a cold snap I went online and sought out accessories in neoprene - a hat, some gloves. I’m yet to wear the shoes, but it’s true what they say: cover your extremities and you’ll stay warm.

Every week we are quietly amazed by our bodies and how quickly they adjust to the water. By the end of the first length we can ignore the cold and take in our surroundings, instead: the glitter of the rising sunlight on the water, the mist of it rising into the air. It all collides as our chests heave. We check in, we keep going, we become familiar with the regulars who swim at the same time as us each week. The ones who power through the fast lane, the ones who meander around the picnic benches and chat as they wriggle in and out of towels.

There are changing rooms at the lido but few people use them. Instead, we stay outside and change under layers, our breath catching in the air. I’m not sure why; a hangover from the summer, when the changing rooms are sweaty and crowded. Now we are here, hopping about on cold feet, and it feels a kind of cop-out to dry off in the warm.

We’re conscious, of course, of the lido’s associations. We cluck over our dry robes, which have become class signifiers and invitations for derision in certain parts of the country. This is south London, there are no waves to wade into, no hilltop reservoirs, no ponds on the doorstep. We feverishly book our slots a week ahead using an app, we moan about how poor the user experience is. I am aware of the innate smuggery that comes with a cold water dip, of the “wild swimming” discourse, of the other women in expensive, practical coats walking towards the low, 1930s building on Dulwich Road. I wear it anyway; it is what it is. In the water, steam rising off your body, everyone becomes a collection of muscle and sinew. This is water is a body, it holds things for people.

We spent much longer chatting over hot drinks from the cafe, waiting for the shivers to subside, than we do swimming. Cake and hats have been provided on birthdays. With time, the sun rises and falls on the tables and we bask in it. Water and light and conversation. We cast forward to what it might be in the winter, when the lido will still be open but the water will be so cold that it would be unwise to stay in long: when the temperature plummets below 10 degrees, the number of minutes you stay in should be matched by the number of celcius. I suspect we’ll still come though. This isn’t fitness, it’s become a kind of ritual.