Chile and Argentina share some of South America’s most dramatic desert landscapes, ranging from the driest place on Earth to one of the largest deserts by area. The main deserts spanning these two countries are the Atacama Desert in northern Chile, the Patagonian Desert across southern Argentina, the Monte Desert in central-western Argentina, and the Puna de Atacama, a high-altitude plateau shared by both nations.
The Atacama Desert in Northern Chile
The Atacama Desert stretches roughly 1,000 to 1,100 kilometers along the northern coast of Chile, wedged between the Pacific Ocean to the west and the Andes mountain range to the east. It sits between roughly 19°S and 30°S latitude, covering several of Chile’s northern administrative regions.
What sets the Atacama apart is its extreme dryness. The hyper-arid core receives less than 1 millimeter of rain per year on average, and some weather stations have gone decades without recording any rainfall at all. This makes it the driest non-polar desert on the planet, and geological evidence suggests it has been hyper-arid for at least 10 million years, making it also one of the oldest deserts on Earth.
That aridity creates a stark, almost otherworldly landscape of sandy soil, salt flats, and stony terrain. The Salar de Atacama, one of the largest salt flats in the region, sits atop brines rich in lithium, potassium, magnesium, and boron. Lithium mining here supplies a significant portion of the world’s rechargeable battery materials. The same bone-dry air and minimal light pollution also make the Atacama one of the premier locations for astronomical observatories, with several major international telescopes positioned at high elevations across the desert.
Despite the harsh conditions, the Atacama supports endemic species found nowhere else. Plants from the passionfruit family have adapted to survive in the desert’s margins, and endemic lizards, bees, and birds occupy ecological niches across the region.
The Patagonian Desert in Southern Argentina
The Patagonian Desert is the largest desert in South America, covering approximately 673,000 square kilometers of southern Argentina. It stretches from about 37°S latitude down to the Strait of Magellan at 51°S, bounded by the Andes to the west and the Atlantic Ocean to the east. The Colorado River forms a rough northern boundary, though the desert extends slightly beyond it in places. Tierra del Fuego, south of the strait, is sometimes grouped with Patagonia as well.
Unlike the Atacama, the Patagonian Desert is a cold desert. Winter temperatures drop to around -4°C in July, while summer highs can reach nearly 38°C in January, with monthly averages swinging between about 8°C and 20°C. The landscape is a vast, windswept steppe of scrub and semi-arid plateau, more reminiscent of Iceland’s interior than the sandy dunes most people picture when they think of deserts. Strong westerly winds are a constant feature, and the rain shadow cast by the Andes is the primary reason the region stays so dry.
The Monte Desert in Central Argentina
Running like a wedge through western and central Argentina, the Monte Desert extends from the Andean foothills in Salta province (around 24°30′S) all the way south to the Atlantic coast in Chubut province (around 44°20′S). That enormous latitudinal range, spanning roughly 20 degrees, means conditions vary widely from one end to the other.
The Monte is classified as arid to semi-arid rather than hyper-arid. Its western and southern boundaries roughly follow the 12°C annual temperature line, though the northern sector is more influenced by mountain topography than latitude alone. Rainfall patterns differ by region: north of about 35°S, moisture comes primarily from Atlantic air masses, while south of 40°S, Pacific air masses slip through lower sections of the Andes and dominate the weather. The Monte has seen a trend of increasing precipitation between 30°S and 40°S in recent decades, particularly during summer months.
The vegetation here is distinct from both the Atacama and Patagonia. Low, drought-adapted shrubs dominate, giving the Monte a scrubby appearance that contrasts with the barren salt flats to the north and the windswept steppe to the south.
The Puna de Atacama: A Shared High Plateau
The one major desert landscape shared directly by both Chile and Argentina is the Puna de Atacama, a cold, high-altitude tableland straddling the Andes in northwestern Argentina and adjacent parts of Chile. It stretches about 320 kilometers north to south and 240 kilometers east to west, sitting at an average elevation of 3,300 to 4,000 meters above sea level. It forms the southernmost extension of the broader Andean Altiplano.
Average temperatures hover around 8.5 to 9.5°C year-round, and the landscape consists of dry, sandy basins alternating with Andean peaks. These basins hold large salt flats, called salinas in Argentina. The biggest include the Antofalla, Hombre Muerto, Arizaro, and Salinas Grandes on the Argentine side, while Chile’s Atacama Salt Flat is the most prominent feature on its side. Vegetation is sparse: mostly low shrubs standing 40 to 150 centimeters high, with a narrow band of broad-leaved trees along the eastern edge where conditions are slightly less punishing.
Desert Parks and Geological Landmarks
Argentina’s desert regions contain some striking geological sites. Ischigualasto Provincial Park and Talampaya National Park sit side by side in the desert on the western edge of the Sierra Pampeanas in central Argentina, together covering about 275,300 hectares. The parks are a UNESCO World Heritage Site, recognized for holding the most complete fossil record of the Triassic Period, roughly 250 to 200 million years ago. Fossils of early dinosaurs, mammal ancestors, and ancient plants are preserved across six distinct geological formations.
The scenery is as remarkable as the fossils. Talampaya features red sandstone cliffs reaching 200 meters high, while Ischigualasto’s white and multicolored sediments create the eerie landscape known as the Valle de la Luna, or Valley of the Moon.
How These Deserts Compare
- Atacama (Chile): Hyper-arid coastal desert, under 1 mm of rain per year in its core, relatively mild temperatures moderated by the Pacific.
- Patagonian (Argentina): Cold semi-arid steppe, the largest desert in South America at 673,000 square kilometers, with harsh winds and wide temperature swings.
- Monte (Argentina): Arid to semi-arid shrubland spanning a huge range of latitudes, with more rainfall variability and warmer conditions than Patagonia.
- Puna de Atacama (Chile and Argentina): High-altitude cold desert at 3,300 to 4,000 meters, dotted with salt flats and low shrubs, the only major desert zone shared by both countries.
Together, these deserts cover a remarkable range of conditions, from the almost lifeless hyper-arid core of the Atacama to the wind-battered steppe of Patagonia, all shaped by the Andes and the interplay of Pacific and Atlantic weather systems.