Chile is one of the world’s most geographically distinct nations, stretching over 2,600 miles along the Pacific coast of South America. This extreme north-south orientation, which spans nearly 38 degrees of latitude, means the country experiences a rapid succession of climate zones. Attempting to define a single “climate of Chile” is impossible, as conditions transition from the driest desert on Earth in the north to the glacial, subpolar tundra of Patagonia in the south.
Geographical Factors Driving Variation
The dramatic climatic shifts are primarily governed by three major physical influences that shape the country’s narrow geography. The most defining feature is the immense wall of the Andes Mountains, which runs the entire length of the eastern border. This towering range creates a powerful rain shadow effect, effectively blocking moisture from the Atlantic Ocean and isolating Chile from the rest of the continent.
The second major influence is the cold Humboldt Current, which flows northward along the Pacific coast from the Antarctic. This cold current chills the overlying air, suppressing evaporation and creating a persistent atmospheric inversion layer near the coast. The stable, cold air mass prevents the formation of rain-producing clouds, which is a key factor in the intense aridity of the northern regions.
The third factor is the sheer latitudinal span, covering nearly 40 degrees from the tropics toward the sub-Antarctic. This range places different parts of Chile under the influence of distinct global atmospheric pressure systems, from the subtropical high-pressure cell in the north to the prevailing, moisture-laden westerly winds of the Southern Ocean in the south.
Climate of the Arid North
The northern third of Chile, extending from the Peruvian border down to roughly the city of Copiapó, is defined by hyper-aridity. This region is dominated by the Atacama Desert, widely regarded as the driest non-polar desert in the world. The interior plateau receives minimal measurable precipitation, with some weather stations recording no rainfall for decades.
This extreme dryness is a result of a double rain shadow, created not only by the Andes to the east but also by the lower Chilean Coast Range to the west, which blocks any residual moisture from the Pacific. The lack of cloud cover leads to exceptionally high solar radiation and a dramatic diurnal temperature range. Day temperatures can be warm, but the lack of atmospheric moisture causes them to drop sharply at night, occasionally approaching freezing.
Despite the interior’s desolation, a unique phenomenon called the camanchaca, or coastal fog, sustains limited life forms along the Pacific edge. Although these thick, low-lying cloud banks rarely yield rain, the moisture they deposit is sufficient to support specialized fog-fed ecosystems, known as lomas, providing a stark contrast to the barren interior.
Climate of the Central Mediterranean Region
The central zone of Chile, stretching from La Serena in the north to Concepción in the south, is home to the majority of the country’s population and features a classic temperate Mediterranean climate. This region, which includes the capital city of Santiago and the port of Valparaíso, is characterized by four distinct seasons. It exhibits hot, dry summers and mild, wet winters.
The summer months, from December to February, are typically arid and sunny, with Santiago recording average high temperatures near 86°F (30°C). During this period, precipitation is negligible, often amounting to only trace amounts. This summer drought is a defining feature of the Mediterranean climate, creating ideal conditions for sun-loving crops.
In contrast, the winter months, from June to August, are cool and receive the bulk of the year’s rainfall. Santiago’s average low temperatures in July drop to around 38°F (3°C), with the average high remaining below 65°F (18°C). The total annual rainfall in this central area increases progressively from north to south, ranging from less than 200 millimeters in the drier northern parts to around 700 millimeters near the southern limit.
This climate is the foundation of Chile’s fertile Central Valley, supporting its productive agriculture, particularly the renowned wine industry. However, recent trends show a concerning shift, with many local farmers reporting perceptions of increased average temperatures and significant decreases in precipitation, indicating a growing frequency of drought conditions.
Climate of the Oceanic South and Patagonia
South of Concepción, the climate rapidly transitions into the Oceanic South, a region of high rainfall and increasing volatility that extends into Patagonia. The Andes, though lower here, intercept the prevailing westerly winds, which are heavily saturated with moisture from the Pacific Ocean. This interaction creates the Valdivian temperate rainforest, where the western mountain slopes receive massive amounts of precipitation, often exceeding 78.7 inches (2,000 millimeters) annually.
This southern zone is characterized by cool summers and wet, moderately mild winters, with rainfall occurring year-round. Moving further south into the Magallanes region and the far reaches of Tierra del Fuego, the climate becomes subpolar oceanic, dominated by constant, powerful winds. Punta Arenas, the region’s capital, is famously windy, with gusts frequently reaching or exceeding 62 mph (100 kph) throughout the year.
The Patagonian climate is highly differentiated by the Andes’ rain shadow, which creates a sharp contrast between the wet, fjord-cut coast and the much drier interior steppes. The eastern side of the Andes, including the Patagonian plains, receives significantly less precipitation, often between 250 and 400 millimeters annually. Temperatures remain consistently cool, with the extreme south rarely seeing summer averages above 48°F (9°C).