Where to go in September, the month serious travellers keep for themselves

There is a reason travel agents used to call September the shoulder season, and it is not simply that the schools go back. The sea has had all summer to warm up and has not yet begun to cool; the crowds that queued for everything in August have gone home; and in a handful of places, the weather does something specific and useful that it does not do at any other time of year. September asks a little more of your diary than August does, but for anyone who can manage it, it tends to pay the difference back.

Paris, arrived at by water

Most visitors reach Paris by train or plane and never see it from the river that built it. A cruise up the Seine from the coast approaches the city the way it grew, past Rouen, with its Gothic cathedral and half-timbered old town, and Vernon, the gateway to Monet's garden at Giverny, before the Eiffel Tower and the bridges of central Paris finally come into view from the water. Norman apple orchards and the chalk cliffs near Le Havre give the early stages of the voyage a very different character from the city at the end of it, and September is precisely when this particular sailing runs, timed to the last of the summer light without the August crowds still filling the Louvre's queues.

Bhutan, in the days after the rains

Bhutan keeps its doors only loosely open at the best of times, and its monsoon, which runs through the summer, closes the high passes to cloud and makes the mountain views that are the point of going largely academic. September is when the rains begin to clear, leaving Paro and Thimphu with sharper air and, with luck, the first proper sightings of the Himalayan peaks that have been hidden since May. It is a short window, and tours through it tend to be short trips too: Paro's dzong and the approach to Tiger's Nest monastery, Thimphu's markets and monasteries, and Punakha, at the confluence of two rivers, all within not much more than a week.

The Aegean, minus the school holidays

Greece in September has the advantage of arithmetic: the sea, which takes months to warm and only slowly cools, is often at its best for swimming precisely as everyone with children has stopped going. A cruise through the Aegean that calls at Mykonos, the monastery-topped island of Patmos, Heraklion on Crete and the caldera at Santorini works considerably better once the ferries and the tavernas are not operating at August capacity, and September's lighter winds make for calmer sailing between islands than the meltemi can produce earlier in the summer.

Each island earns its stop for a different reason. Mykonos is the famous one, all white cubes and windmills, and is genuinely more pleasant to walk around once the peak crowds have thinned. Patmos is quieter and older in spirit: this is where the Book of Revelation is traditionally said to have been written, in a cave still shown to visitors on the hillside above the harbour. Heraklion is the gateway to Knossos, the Bronze Age palace complex excavated by Arthur Evans, and Santorini closes the trip with the cliffside towns of Fira and Oia stacked above the flooded volcanic caldera that gives the island its shape.

Choosing your September

If you want a single, elegant journey that arrives somewhere unmistakably grand, the Seine into Paris is hard to beat, and it needs no more stamina than a week on a boat with excellent food. If you have ever wanted to see Bhutan and worried you had missed the moment, September is as close to a guarantee as that country offers. If you simply want the Greek islands without the crowds that come with them all summer, wait for the schools to go back and go then; the sea will still be waiting.