<P> The Danube is by far Romania's most important river, not only for transportation, but also for the production of hydroelectric power . One of Europe's largest hydroelectric stations is located at the Iron Gates, where the Danube surges through the Carpathian gorges . The Danube is an important water route for domestic shipping, as well as international trade . It is navigable for river vessels along its entire Romanian course and for seagoing ships as far as the port of Brăila . An obvious problem with the use of the Danube for inland transportation is its remoteness from most of the major industrial centers . Moreover, marshy banks and perennial flooding impede navigation in some areas . </P> <P> Because of its position on the southeastern portion of the European continent, Romania has a climate that is transitional between temperate and continental . Climatic conditions are somewhat modified by the country's varied relief . The Carpathians serve as a barrier to Atlantic air masses, restricting their oceanic influences to the west and center of the country, where they make for milder winters and heavier rainfall . The mountains also block the continental influences of the vast plain to the north in Ukraine, which bring frosty winters and less rain to the south and southeast . In the extreme southeast, Mediterranean influences offer a milder, maritime climate . The average annual temperature is 11 ° C (51.8 ° F) in the south and 8 ° C (46.4 ° F) in the north . In Bucharest, the temperature ranges from − 29 ° C (− 20.2 ° F) in January to 29 ° C (84.2 ° F) in July, with average temperatures of − 3 ° C (26.6 ° F) in January and 23 ° C (73.4 ° F) in July . Rainfall, although adequate throughout the country, decreases from west to east and from mountains to plains . Some mountainous areas receive more than 1,010 mm (39.8 in) of precipitation each year . Annual precipitation averages about 635 mm (25 in) in central Transylvania, 521 mm (20.5 in) at Iași in Moldavia, and only 381 mm (15 in) at Constanța on the Black Sea . </P> <P> Temperate; cold, cloudy winters with frequent snow and fog; sunny summers with frequent showers and thunderstorms . Winters generally are from November to March . The springs are short, occasionally turning right into summer . Summer lasts from May to August . They have a prolonged Autumn, from September to November . The average January temperature is 34 ° F (1.1 ° C) and the average July temperature is 69 ° F (20.6 ° C). Facts: Record High Temperature: 44.5 ° C (112.1 ° F) - August 10, 1951 South - Eastern Romania; Record Low Temperature: − 38.5 ° C (− 37.3 ° F) - January 24, 1942 (Central Romania) </P> <P> Southeastern Europe, bordering the Black Sea and Danube, with the Carpathian mountains in its center . Controls most easily traversable land route between the Balkans, Moldova and Ukraine </P>

What plain stretches across croatia serbia and romania