That morning we woke to snow, furry flakes falling fast onto a thin carpet of white on the ground. I didn’t look out the window and think, “I must swim in that.” I thought instead that maybe I would stay by the fire and read all day, looking at the towering white peaks through the comforting barrier of a pane of glass before returning to my cosy indoor existence.

But by the afternoon the snow had stopped and we ventured out. We drove to a favourite spot on the west shore of Windermere, Red Nab, and walked under the cover of trees. I swam here very early in my outdoor swimming adventures. It’s quiet and there are natural tree shaded coves. The water quickly gets deep enough to swim and you can be out under the open sky within a few strokes, looking back at the trees twisting their roots along the bank.

Today as we walked we were treated to a thirty second hail storm, chunks of ice flying at our faces, gathering under our chins in the folds of scarves. By the time we returned to our start point the light was fading into that strange dotted dusk where you can’t quite trust your eyes. But the water was stunningly clear and I was so tired. I was warm in my layers and I wanted to wake up. And so I went in.

Changing was bad enough, the air cold from the vagaries of the weather. I’ve learnt not to test the temperature with a hand or foot, for the instant bone freeze in these fat-less parts can be enough to convince yourself it’s impossible. Though my feet were instantly frozen through my trusty swim socks, the flesh of my legs handled it better. This isn’t so bad, I thought, though I was gasping.

It’s the push off that’s coldest, when the water closes over your chest. I have to go on three or I won’t go. And this cold, post snow and hail, crystal clear but frigid water forced constant scream-gasps from me. I swam out, looked back at the mountains and felt stinging all over. There were small waves at the bank and I returned to the shallows. The outside of my arms, the undersides of my thighs stayed cold the longest, even when I was in the car with the blow heater on. But somehow I wasn’t so tired anymore. When I got home I found twigs and small pieces of weed stuck to my legs from changing on the bank, pressed tight to my flesh by my thermals.

I’m raising money for the Alzheimer’s Society. Please sponsor me at http://www.justgiving.com/swimbonnieswim