A vast gravel desert plain covers most of central Oman, with mountain ranges along the north (Al Hajar Mountains) and southeast coast, where the country's main cities are also located: the capital city Muscat,Sohar and Sur in the north, and Salalah in the south.
Coast of Sur, Oman
Oman's climate is hot and dry in the interior and humid along the coast. During past epochs Oman was covered by ocean. Fossilized shells exist in great numbers in areas of the desert away from the modern coastline.
The peninsula of Musandam (Musandem), which has a strategic location on the Strait of Hormuz, is separated from the rest of Oman by the United Arab Emirates and is thus an exclave. The series of small towns known collectively as Dibba are the gateway to the Musandam peninsula on land and the fishing villages of Musandam by sea. Boats may be hired at Khasab for trips into the Musandam peninsula by sea.
Oman has another exclave, inside UAE territory, known as Madha. It is located halfway between the Musandam Peninsula and the rest of Oman. Belonging to Musandam governorate, it covers approximately 75 km2 (29 sq mi). The boundary was settled in 1969. The north-east corner of Madha is closest to the Fujairah road, barely 10 m (32.8 ft) away. Within the exclave is a UAE enclave called Nahwa, belonging to the Emirate of Sharjah. It is about 8 km (5 mi) on a dirt track west of the town of New Madha. It consists of about forty houses with its own clinic and telephone exchange.
Annual rainfall in Muscat averages 100 mm (3.9 in), falling mostly in January. Dhofar is subject to the southwest monsoon, and rainfall up to 640 mm (25.2 in) has been recorded in the rainy season from late June to October. While the mountain areas receive more plentiful rainfall, some parts of the coast, particularly near the island of Masirah, sometimes receive no rain at all within the course of a year. The climate generally is very hot, with temperatures reaching 54 °C (129.2 °F) in the hot season, from May to September.