Omani men wear the dishdasha: an ankle-length, collarless robe, most often white or a pale neutral, with a small tassel at the neck and an embroidered cap or a wrapped turban above it. It is worn to the office, to the souk and to dinner, and it contains everything a visitor needs to know. The garment is long, it is loose, it is light in colour and it covers the body. Nobody expects a guest to adopt it. But a man working out what to wear in Muscat can do no better than to follow its logic in his own idiom, and linen is the cloth that allows him to.

In practice that means long trousers and a shirt with sleeves whenever he is in the city itself. Muscat is relaxed and hospitable, and inside the resorts shorts are entirely normal. In the souq, in government buildings, in older neighbourhoods and in the villages of the interior, shorts above the knee and sleeveless tops are considered poor manners in a man as much as in a woman. PP Casual Linen Trousers in Oatmeal or Vanille and PP Trousers 100% Linen in White are the base of the wardrobe, with the Laos Long Sleeve Linen Shirt in Oyster, Beige Cream or Dark Blue above them.

Mutrah is the old commercial harbour, and it is at its finest in the last hour of light. The corniche curves beneath watchtowers and merchants' houses with carved balconies; the souq runs back from the waterfront under a timber roof, smelling of frankincense and sandalwood. It is a place to walk slowly. The same long trousers serve, with a Laos Short Sleeve Linen Shirt in White or Vanille if the evening is warm. The fish market at the port end of the corniche is a morning visit, with wet floors, and is one occasion on which a shirt in a darker colourway such as Dark Blue is the practical choice.

Evening in Muscat can be formal. The Royal Opera House, in the Shatti Al Qurum district, asks its audience for smart or formal dress. A long-sleeve collared shirt with long trousers and closed shoes is the starting point, a jacket is commonly worn over it, and the house's current dress code is worth reading before the evening. The Monte-Carlo Male in Oyster or Vanille, with walnut buttons, pressed for once, sits well beneath a jacket. Dinner at the city's larger hotels is less strict but follows the same spirit after dark. This is the one part of a Muscat stay for which linen is worth ironing, and the Journal's guide on how to iron linen describes the method.

The sea is half the reason to come. Boats leave the marina at Al Mouj for the Daymaniyat Islands, a protected group of small islands about an hour offshore, where the snorkelling is over coral and green turtles are commonly seen. On the boat and in the sea a man wears PP natural swim shorts; Sapphire Blue, Oatmeal and Black are the quieter colourways. A linen shirt goes on over dry skin for the return, when the sun on an open deck is at its strongest. On public beaches away from the hotels, swimwear is for the water's edge and a shirt is worn to and from it.

Many visitors add a day or two inland. Nizwa, with its round fort and its Friday livestock market, lies about an hour and a half from the capital, and above it the terraced villages of Jebel Akhdar sit at around two thousand metres, where the air is noticeably cooler than on the coast and distinctly cold on winter nights. Linen still serves by day, but the mountains call for a proper extra layer after sunset. The wadis, where people walk and swim in freshwater pools, follow the etiquette of the public beach: swim shorts to the knee, a shirt on the path.

As for season, Muscat is at its most agreeable from about November to March, with warm, dry days and mild evenings. October and April are hotter. The summer is extremely hot and humid on the coast, and life moves indoors for the middle of the day. Whatever the month, pale colourways are cooler in direct sun. PP's atelier is in Dubai, in the neighbouring Emirates, and the garments are handmade there and in Belgium, chiefly in certified Belgian linen.

Oman rewards a visitor who notices how people dress and takes the hint. Long, loose, pale, covered, and made of something that breathes: the dishdasha set the terms long ago.

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