The trouble with booking a holiday home in late September, I have since learned, is that you convince yourself you are being terribly clever and avoiding the crowds, when in fact you are mostly just avoiding reliable weather and any chance of finding a shop that has not already packed away its swimming costumes to make room for olive oil and truffle-flavoured everything.

Our journey to Umag had begun with the sort of overconfidence that only a British person in a hire car can truly muster. We had flown into Pula, collected a Fiat that smelled faintly of pine air freshener and regret, and set off north with the windows down and a playlist of questionable summer hits blaring. The sat nav, which I suspect had never encountered a Croatian country lane, grew increasingly hysterical as we approached Crveni Vrh, directing us through what appeared to be someone's vineyard, then a field of very surprised goats, and finally down a track so narrow that I found myself holding my breath and the passenger door mirror simultaneously.

The mishap came at the final junction. I spotted what I thought was the turning to our holiday home, a smart-looking place with a terrace and a pool, according to the photographs. I swung the Fiat in with the triumphant air of a man who has navigated foreign roads without incident. The gate opened automatically, which felt encouraging. We crunched up the gravel drive, admiring the bougainvillea and the neat rows of lavender. I was already rehearsing my casual remark about how easy the whole thing had been when a woman emerged from the house holding a watering can and looking at us with the expression of someone who had not been expecting visitors, least not visitors in a dented Fiat playing "Summer of '69" at considerable volume.

It was not our holiday home. It was, I later gathered, a rather expensive private villa belonging to someone from Zagreb who used it precisely three weekends a year. The automatic gate had opened because they had left it on a timer for their gardener. I reversed out with what dignity I could muster, which is to say none whatsoever, while the woman watched from her doorway with the watering can still poised, as if considering whether to water us off her property.

Our actual place was two hundred metres further on, slightly more modest, and mercifully lacking an audience. By then the afternoon had turned that particular soft gold that comes to Istria in late September, when the harsh summer light has mellowed and the air carries a faint chill that makes you grateful for a jumper but not yet desperate for a coat. The pool, which in July would have been the centre of all activity, sat there looking rather philosophical, too cold for swimming but too pretty to ignore entirely. I dipped a toe and confirmed what my goosebumps already knew: the season for aquatic bravery had passed.

This became the rhythm of those first days. We would wake to mist rolling in from the sea, burning off by mid-morning to reveal skies of almost embarrassing blueness. The terrace, where we took our coffee, was warm enough by ten o'clock to fool you into thinking summer lingered, but the shadows grew long by four and the evenings demanded blankets and a proper fire in the little stone barbecue. The local shop, when we found it, had indeed transitioned to autumn stock. I asked hopefully about beach towels and was directed to a shelf containing three faded options and a large selection of local honey. I bought honey instead, and have no regrets.

The golf course nearby, which in peak season would have been busy with Germans and Austrians in alarming trousers, was virtually empty. We walked its edges in the mornings, watching groundskeepers prepare the greens with the unhurried pace of men who knew their serious season had ended. The sea, visible from our terrace, had turned from the bright turquoise of postcards to something deeper and more serious, though no less beautiful. A few hardy souls still swam at the little beach below, emerging pink and triumphant, but I contented myself with rocky walks and the occasional paddle, yelping at the cold like the fully acclimatised British coward I am.

What struck me most, that first week, was how the place revealed itself differently than it would have in July. The restaurants in Umag old town, rather than turning tables twice an evening, welcomed us in for long unhurried meals where the waiter had time to explain the wine list and recommend a particular olive grove. The truffle hunting demonstrations, which in summer feel like tourist theatre, had the authentic air of proper autumn work. One morning we followed our noses to a nearby vineyard where they were pressing the last of the grapes, and stood drinking young wine in the sunshine with our fingers sticky from sampling figs off a tree that no one had bothered to harvest properly.

There is something slightly melancholy about arriving somewhere just as it is closing down for the year, a feeling of having missed the party but been invited to the quiet conversation afterwards. I felt this particularly on our third evening, sitting by the pool with a blanket and a glass of Malvasia, watching the sun drop behind the pine trees. The pool lights came on automatically, illuminating water I knew I would not swim in, and I found myself reflecting on how my younger self would have insisted on a dip regardless, would have made a performance of the bravado, would have cared more about saying I had done it than about whether I actually enjoyed it.

I still did not swim. I finished my wine and went inside to put the heating on, perfectly content.