The central highlands are an extensive high plateau over 2,000 metres (6,560 feet) in elevation. This area is drier than the western highlands because of rain-shadow influences, but still receives sufficient rain
in wet years for extensive cropping. Diurnal temperature ranges are among the highest in the world: ranges from 30 °C (86 °F) in the day to 0 °C (32 °F) at night are normal. Water storage allows for irrigation
and the growing of wheat and barley. Sana'a is located in this region. The highest point in Yemen is Jabal an Nabi Shu'ayb, at 3,666 meters (12,028 ft).
Yemen is in the Middle East, in the south of the Arabian Peninsula, bordering the Arabian Sea, Gulf of Aden, and Red Sea, west of Oman and south of Saudi Arabia. Tihama on the Red Sea near KhaukhaA number of Red Sea islands, including the Hanish Islands, Kamaran and Perim, as well as Socotra in the Arabian Sea belong to Yemen. Many of the islands are volcanic; for example Jabal al-Tair had a volcanic eruption in 2007 and before that in 1883. At 527,970 km² (203,837 sq mi), Yemen is the world's 49th-largest country (after France). It is comparable in size to Thailand, and somewhat larger than the U.S. state of California. Yemen is situated at 15°N 48°E / 15, 48.
Its territory includes a number of islands in the waters around it. The most well-known of these are the Hawar Islands, Halul which is the export terminal for the offshore oil fields and others.
Remittances from Yemenis working abroad and foreign aid paid for perennial trade deficits. Reports average annual growth in the range of 3-4% from 2000 through 2007. Its economic fortunes depend mostly on declining oil resources, providing around 90% of the country's exports. The World Bank predicts that Yemen's oil and gas revenues will plummet during 2009 and 2010, and fall to zero by 2017 as supplies run out, and UK's Royal Institute for International Affairs warns that instability there could expand a zone of lawlessness from northern Kenya to Saudi Arabia, while describing Yemen's democracy as "fragile" and pointing to armed conflicts with Islamists and tribal insurgents. Thus western and other diplomats and leaders are concerned to preserve Yemen's stability and to avert adverse outcomes.