Poland has two main regions—the Polish Plain and the Southern Uplands and Mountains. They run roughly east-west and become progressively higher from north to south.
The Polish Plain covers the northern two-thirds of the country. It is part of the Great European Plain, which spans the continent from France to Russia. Making up the plain are thick deposits of debris left by retreating glaciers during the last Ice Age. Some of the land is marshy and poorly drained.
Lagoons, sandy beaches, and dunes fringe much of the Baltic coast. Inland, the surface rises to a broad tract of level to rolling land, sometimes called the Baltic Heights. It contains numerous lakes, moraines, and glacial hills, which in places rise to elevations of 1,000 feet (300 m). The southern part of the plain spans central Poland and is a wide, almost level lowland. The lowest point in Poland is near Elbląg in the north of the country at 7 feet (2 m) below sea level.
The Southern Uplands and Mountains cover the southern third of Poland. Except for the Carpathian Mountains, the region is part of an old, worn-down, mountainous belt, sometimes called the Hercynian Uplands. It is a region of escarpments, mountain ranges, low-lying plateaus, and partly enclosed basins. Chief among surface features are the Sudeten Mountains, in the southwest along the Polish-Czech border, and the adjacent coal-rich Silesian Basin. Other features include the Swiětokrzyskie Mountains and the Lubelska Upland.
The Carpathians are a chain of young folded mountains stretching along the Polish-Slovakian border in the southeast. They include the Beskid ranges and the rugged Tatra Mountains. Rysy, the highest mountain in Poland, rises 8,199 feet (2,499 m) in the Tatras.
Most of Poland is drained by two large rivers—the Oder (Odra in Polish) and the Vistula (Wisla). Both flow northward in S-shaped courses to the Baltic. Other rivers include the Bug, San, Narew, and Pilica—tributaries of the Vistula—and the Warta, Noteć, and Nysa Luzycka—tributaries of the Oder.
Nearly all of Poland's lakes are in the north in the Baltic Heights; the largest ones are Lakes Śniardwy and Mamry.
Poland's climate is transitional between the tempered, oceanic climate of northwestern Europe and the severe, continental type of Russia. Weather is extremely changeable; seasons are well marked.
Along the Baltic coast, where the sea's influence is strongest, summers are cool and winters are relatively mild for the latitude. Temperatures average about 63° F. (17° C.) in July and 31° F. (-1° C.) in January. The interior of the country, especially the southeast, has slightly warmer summers and colder winters. At Warsaw, for example, the average for the warmest month is 67° F. (19° C.) and for the coldest month, 27° F. (-3° C.). The Carpathian and Sudeten mountains, because of their elevation, have relatively low temperatures throughout the year.
Precipitation averages about 20 to 25 inches (510 to 640 mm) on the plain and in the upland areas. It is 60 inches (1,520 mm) or more in the Carpathians. Normally, snow covers the ground from one to three months, depending on location.