Physical Geography

Portugal lies at the western edge of the Spanish Meseta, a vast tableland dominating the Iberian Peninsula. Landforms consist mainly of moderately high plateaus and mountains sloping south westward to lowlands along the Atlantic coast.

Northern Portugal—the area north of the Tagus River—is the most rugged part of the country. Here, behind a coastal lowland up to 30 miles (48 km) wide, mountains rise to heights of generally less than 5,000 feet (1,520 m). The highest range is the Serra de Estrela, which runs northeast-southwest and reaches a maximum elevation of more than 6,500 feet (1,980 m). There are also flattopped plateaus cut by deep river valleys, especially in the northeast.

Southern Portugal is made up primarily of coastal lowlands, broad river valleys, and low, almost flat plateaus. Only along the Spanish border and in the extreme south are there mountains, most of which are low.

Portugal is drained by three major rivers, all flowing from the Spanish Meseta: the Tagus, Douro, and Guadiana. Other rivers include the Minho, Mondego, and Sado. Because of distinct wet and dry seasons, the rivers flow irregularly; many dry up completely during the summer. Principal lakes are reservoirs, impounded mainly for hydroelectric power on the Douro and Tagus rivers.

Prevailing in the south is a Mediterranean type of climate similar to that of southern California. Summers here are long, hot, and dry; winters are mild and relatively rainy. Normally, average temperatures range between 50° F. (10° C.) in January and 80° F. (27° C.) in July. Throughout most of this area, freezing temperatures and snow are unknown. Rainfall totals about 20 inches (510 mm) a year.

Northern Portugal, because of greater oceanic influences and higher elevations, has a more temperate climate. Winters are cooler and summers are milder than are those in the south; average January and July temperatures are about 40° F. (4° C.) and 70° F. (21° C.). Frosts frequently occur in winter; snow occasionally blankets the high mountains. Precipitation exceeds 30 inches (760 mm) annually. The dry season is neither as long nor as pronounced as in the south.