Most of Ukraine is made up of flat or gently rolling plains, interrupted in places by hills and ridges. In the north are marshes and wooded lowlands. The central region consists generally of wooded steppes, where oak, maple, pine, and beech trees thrive. In southern Ukraine open steppes prevail. The Carpathian Mountains rise in the west, reaching nearly 6,800 feet (2,070 m). The mountains of the Crimean Peninsula are slightly lower, reaching about 5,100 feet (1,550 m).
Several major rivers cross Ukraine. The Dnieper, Ukraine's longest, enters the country from Belarus and flows into the Black Sea. Other large rivers include the Donets, Bug, and Dniester. Ukraine has no large natural lakes but several reservoirs have been created by dams on the Dnieper. These dams are important sources of hydroelectric power.
Ukraine's climate, with some exceptions, is temperate. In summer the temperatures generally become progressively warmer from west to east; in winter they become progressively colder. The average July temperature in Kiev is 69° F. (20° C.); in January it is 21° F. (-6° C.). Precipitation is heaviest in the north and northwest, where it averages 24 to 28 inches (600 to 700 mm) annually. The driest areas are in the south, with an annual average of 16 to 20 inches (400 to 500 mm). Throughout Ukraine, summer is the wettest season.
The southern Crimean coast, sheltered by the mountains and warmed by the sea, has a Mediterranean climate.