Eleven of us swim in the lakes around Zarasai all year, and I keep the log: water readings, ice conditions, how long anybody stayed in, and the habits we built after the mornings that went badly.

Cold Lake Swimmers is eleven or twelve people, a bag of towels, and a hole in the ice from December to March. It started in the autumn of 2020, when two of us worked out that we had been swimming off the same jetty on the same mornings for a month without saying anything. The lakes around Zarasai are shallow, weedy at the edges and honest about the season: they warm quickly through June and give all of it back by the end of October.

I write the entries. The temperatures here are read off a cheap glass thermometer on a bootlace at knee depth, usually while somebody stands behind me complaining about the wind. Nothing is measured to a standard anybody else would recognise, and I would not trust our figures for anything except deciding how long to stay in. What the log is for is memory across a whole year, because a lake in March behaves nothing like the same lake in November at the same reading.

Nothing here is instruction. Cold water does different things to different bodies, this group holds no qualification worth mentioning between us, and the habits in these entries were built for one shallow lake district and a particular set of people who have swum together for years. I use nobody's name, I photograph nobody, and I leave out the exact spot where we cut in winter: an ice hole found by a stranger in the dark is a hazard rather than an invitation.