Italy has three major physical regions: the Alps, the Po Valley, and the Apennines.
The Alps, in the north, are a massive arc of rugged, geologically young mountains following Italy's border from France to Slovenia. The highest peaks, mantled by ice and snow the year round, rise more than 14,000 feet (4,300 m) above sea level along the Italian-Swiss border. Included are Monte Rosa (15,203 feet [4,634 m]) and the Mat-terhorn (14,690 feet [4,478 m]). Mont Blanc, western Europe's highest peak, lies partly in Italy, but crests just beyond the border in France at 15,771 feet (4,807 m).
The loftiest peak entirely within Italy is 13,323-foot (4,061-m) Gran Paradiso in the Graian Alps, one of the westernmost ranges. Eastern ranges, including the craggy Dolomites, are generally lower than those in the west, but are nevertheless rugged. Numerous alpine passes provide access to the north. Probably most famous are the Brenner, Great St. Bernard, and St. Gotthard passes.
The Po Valley, at the base of the Alps, is a relatively flat, triangular plain. It extends from near Turin to the head of the Adriatic, where it reaches a width of about 150 miles (240 km). Similar terrain extends northeastward in a fairly broad band toward the Slovakian border. Agriculturally and industrially, the Po Valley is Italy's richest, most intensively developed area.
The Apennines, making up the largest of the three regions, consist of a mountain chain running the length of the peninsula. Like the Alps, the Apennines are geologically young mountains, but they are lower and less rugged than the Alps. The maximum height, 9,554 feet (2,912 m), is reached at Corno Grande in the Gran Sasso d'Italia range, northeast of Rome. Breaking the rough-to-rugged Apennine terrain in numerous places are broad river valleys, basins, and plateaus. Narrow plains parallel much of the coast. At the toe of Italy's boot the Apennines drop beneath the Strait of Messina, reappearing on the island of Sicily as locally named ranges. Sardinia, Italy's other large island, is also mountainous.
Earthquakes are relatively frequent in Italy, especially in the Apennines, where several devastating quakes have occurred during the past century. Volcanoes, mainly dormant or extinct, dot the western Apennine slopes and occur on several offshore islands. Active volcanoes include Ve-suvius, near Naples; Etna, on Sicily; and Stromboli, in the Tyrrhenian Sea.
Italy's chief river is the 418-mile (673-km) Po, which is fed primarily by the waters of countless alpine streams. Major tributaries include the Dora Baltea, Ticino, Adda, and Oglio. Second to the Po in length and annual flow is the Adige, which empties into the Adriatic just north of the Po. Many of the rivers in the Alps have been dammed, primarily for hydroelectric power.
Rivers of the peninsula, including the Arno, Tiber, and Volturno, are small compared to those in the north. Virtually, all of them have a greatly reduced flow in summer.
Glacial lakes nestle in some of the alpine valleys. The largest ones—renowned for their great natural beauty and known collectively as the Italian Lakes—are situated in the foothills of the Alps. Among them are Lakes Maggiore and Lugano, which lie partly in Switzerland, and Lakes Como, Iseo, and Garda. The most famous section of Italy's 2,300-mile (3,700-km) coast is the Italian Riviera. Its resort-lined beaches, backed by abruptly rising mountains, stretch along the Ligurian Sea from the French Riviera to La Spezia. The section west of Genoa is known as the Riviera di Ponente; the section east of Genoa, the Riviera di Levante.
The climate of Italy varies considerably, mainly because of the country's 700-mile (1,130-km) span of latitude, the influence of high mountains, and the effects of adjacent seas.
The peninsula, south of the Po Valley, has a Mediterranean climate, similar to that of southern California. Summers are hot and dry; winters are mild and relatively rainy; bright, sunny weather prevails throughout most of the year. Temperatures in Rome, for example, average 77° F. (25° C.) in July and 46° F. (8° C.) in January. There is relatively little freezing weather. Annual precipitation varies from about 25 to 40 inches (635 to 1,020 mm), depending on location. Rainfall in Rome averages about 30 inches (760 mm) a year. The south is generally drier than the north, the east coast drier than the west. The Riviera has a similar climate, but receives slightly more precipitation.
The Po Valley has a somewhat harsher climate, one resembling the continental type of central Europe. Winters are chilly or cold and often damp and foggy. Summers are much like those in the south. Temperatures in Milan, for example, average about 36° F. (2° C.) in January and 75° F. (24° C.) in July. During the coldest month freezing weather and snow usually occur.
The Alps have cool summers, severe winters, and abundant rain and snow. The high peaks are perpetually cold.
Italy's vegetation is as varied as its terrain and climate. Nowhere is plant life abundant, however. Because of the dry summers, especially in the south, drought-resistant species predominate. Chief groups include low evergreen plants, thickleaved shrubs, thorny scrub, and cacti.
Oaks and several species of small pines are among the trees native to the lowlands and low mountain slopes. Poplar and willow often line riverbanks. In the Alps and Apennines such deciduous trees as oak, chestnut, and beech grow at mid-slope. Fir, pine, and other conifers are found higher up. Alpine meadows occur above the timber line.
Few large animals are still to be found in Italy. Bears, wolves, chamois, ibexes (wild goats), deer, and wild boars are among those surviving in the high mountains, mainly in national parks. Birds are numerous and varied. Italy has few snakes.