The climate of Saudi Arabia varies from one province to another. The Kingdom lies in the tropics, and the nationwide average temperature is 18°C (64°F). Local average vary considerably from 24°C (75°F) in the Western Province, rising as we descend towards the southwest until it reaches 28°C (82°F) in Jeddah and 30°C (86°F) in Jizan. In the northwest, the average temperature is 22°C in Tabouk and 28°C in Madinah, which is 850 meters above the sea level. In the Asir region in the southwest, the average temperature is only 19°C because of the high altitude. The central province, which is surrounded by desert, has an average of 25°C for Riyadh, 21°C in Hai'l and 23°C in Qaseem. In Dhaharan, the eastern Province, the temperature is an average of 26°C. Apart from topographical factors, Saudi Arabia's climate is also affected by tropical winds which cause monsoons the west and southwest. These occur during the summer months. In the south, tropical continental winds blow particularly in winter often accompanied by sandstorms.
Saudi Arabia is one of the driest countries in the world, with rainfall averaging less than 5 inches per year. Marked seasons, in the European or American sense, do not exist.
The climate is principally determined by the southerly shift in wind patterns during the winter months which brings rain and cool weather.
Other factors such as latitude, proximity to the sea and altitude, also affect the climate. In the Empty Quarter, the great southeastern sand desert, ten years may pass with no rain. The Asir Highlands in the south receive rainfall due to the monsoon that may exceed 255mm (10 inches) per year. Jeddah, on the shores of the Red Sea, has a hot and humid climate year-round. Taif, on the other hand, and Abha, enjoy much more temperate weather.
Summer is hot with temperatures in some areas reaching 49°C (120°F). Winter is cooler with an average temperature of 23°C (74°F) in Jeddah and 14°C (58°F) in Riyadh. Winter temperatures drop below freezing in the central and northern parts of the country and snow and ice sometimes occur in the higher elevations in the south-west.
In areas where there is little ground cover, a northwesterly wind blows for most of the summer months and may, especially in the eastern part of the country, whip up violent sandstorms.
Between October and May is generally pleasant with cool nights and sunny days. Night temperatures in the coastal areas may dip into the 40s (Fahrenheit). From April to November, on the other hand, temperatures are considerably higher and life without air-conditioning would be very unpleasant indeed.
