Saudi Arabia is overwhelmingly a hot desert, with roughly 80% of the country classified as arid. Summer temperatures in the interior regularly exceed 100°F, rainfall is minimal across most regions, and the landscape ranges from vast sand seas to surprisingly cool mountain highlands. But the climate is not uniform. Coastal humidity, southwestern monsoons, and elevation create distinct pockets that feel nothing like the scorching interior.
A Desert Country With Regional Exceptions
The dominant climate type across Saudi Arabia is hot desert, technically classified as BWh under the Köppen system. That translates to extreme daytime heat, very little rain, and wide swings between day and night temperatures. This describes most of the central plateau, the northern plains, and the massive sand desert known as the Rub’ al Khali, or Empty Quarter, in the south.
The major exception is the southwestern corner. The Asir Mountains, which rise above 9,000 feet along the Red Sea escarpment, receive enough rain to support a mild steppe climate with green terraces and juniper forests. If you picture Saudi Arabia as nothing but sand dunes and flat desert, the southwest would surprise you.
Summer and Winter Temperatures
Riyadh, the capital and a good proxy for the interior, has a hot season lasting over four months, from mid-May through late September. July is the peak: the average high reaches 110°F, with lows around 86°F. Even overnight, the air stays oppressively warm. By contrast, Riyadh’s winters are genuinely cool. January averages a high of 69°F and a low of 49°F, comfortable enough for a light jacket at night.
The Empty Quarter pushes temperatures further. Daytime highs above 95°F are typical from early May through mid-October, and nighttime temperatures stay above 86°F from June through September. Because the air is so dry, the desert also experiences dramatic cooling after sunset during spring and early summer, when the difference between daytime and nighttime temperatures is at its largest.
Despite its reputation for heat, Saudi Arabia does get cold. The lowest temperature ever recorded in the country was minus 10°C (14°F) in the northern city of Hail on January 16, 2008. That same winter, Riyadh dropped to minus 5.4°C, and several northern cities recorded sub-zero readings. The year 2008 was among the coldest on record nationally, but freezing temperatures in the north are not unheard of in other years.
Coastal Humidity vs. Dry Interior
One of the biggest climate divides in Saudi Arabia is between the coasts and the interior. Jeddah, on the Red Sea, averages around 55% relative humidity year-round, peaking near 62% in September and rarely dropping below 47% even in the driest month. Inland cities like Tabuk average just 29% humidity, and afternoon readings there can fall as low as 16%. That difference fundamentally changes how the heat feels. A 100°F day in Riyadh, while brutal, is dry enough that shade and airflow offer some relief. The same temperature in Jeddah, layered with humidity, can feel dangerously oppressive.
The Persian Gulf coast on the eastern side is similarly humid. Cities like Dhahran and Dammam combine high heat with moisture from the shallow Gulf waters, making summer heat index values significantly worse than the actual air temperature.
Rainfall: Scarce and Unpredictable
Saudi Arabia receives very little rain overall. The national average peaks in April at just under 16 mm for the month, while June averages barely 1.5 mm. Most of the country’s rain falls between November and April, delivered by weather systems sweeping in from the Mediterranean. The rest of the year is essentially dry.
Rainfall also varies enormously by location. The Empty Quarter receives roughly 30 to 40 mm per year, barely enough to wet the sand before it evaporates. The Asir Mountains are the outlier. Influenced by the Indian monsoon system, typically between October and March, the Asir region receives around 300 mm of rain during that window alone, accounting for about 60% of its annual total. Condensation driven by the steep mountain slopes adds even more moisture. The result is a rainfall pattern with two peaks: a stronger one in spring and a secondary one in summer. During El Niño years and certain Indian Ocean conditions, moisture transport from the Red Sea increases, boosting Asir’s rainfall further.
Shamal Winds and Dust Storms
Saudi Arabia’s other defining weather feature is wind-driven dust. The Shamal, a persistent northwesterly wind, blows across the eastern Arabian Peninsula each summer. The season typically starts around May 30 and ends around August 16, though the timing shifts by a few weeks depending on the year. High pressure over the eastern Mediterranean and low pressure over Iran and Pakistan create the pressure gradient that drives these winds.
During active Shamal periods, visibility can drop dramatically as fine sand and dust are lifted thousands of feet into the atmosphere. The frequency of dust storms tracks closely with the number of Shamal days in a given summer. Years with an early onset tend to coincide with La Niña conditions in the Pacific, while El Niño years generally delay and shorten the season.
The Southwest Highlands
The Asir region and parts of the southern Hijaz sit at elevations high enough to create a genuinely different climate. Temperatures are cooler year-round, sometimes 20 to 30 degrees Fahrenheit below what the lowland deserts experience on the same day. The city of Abha, at roughly 7,200 feet, is one of the few places in the country where summer temperatures remain mild.
This elevation also catches moisture that the rest of the country misses. Orographic lift, where air is forced upward by mountain slopes and cools enough to produce rain, supplements the monsoon-driven precipitation. The combination makes the southwest the wettest part of Saudi Arabia by a wide margin, supporting agriculture and vegetation that would be impossible elsewhere in the kingdom.
How the Climate Is Shifting
Projections from a joint MIT and Saudi research team paint a concerning picture for mid-century. Using high-resolution climate models focused on the 2041 to 2050 window under a high-emissions scenario, the researchers projected rising temperatures across all five strategic locations they studied: Riyadh, Makkah, Madinah, Tabuk, and Jeddah.
Jeddah faces a particular risk. The combination of rising heat and humidity is expected to produce an increasing number of extreme heat index days, threatening the basic habitability of the coast during peak summer. Meanwhile, the western mountains are projected to see more intense and frequent rainfall events in August, raising flood risks. In the opposite direction, the Empty Quarter and surrounding southern desert are expected to receive even less rain than they do now, further depleting already scarce water resources. The overall trajectory is a country that gets hotter, more humid along its coasts, and drier in its interior, all at the same time.