Differences in elevation, proximity to the Adriatic Sea and large river basins, as well as exposure to the winds account for climate variations. Southern Serbia is subject to Mediterranean influences. The Dinaric Alps and other mountain ranges contribute to the cooling of most of the warm air masses. Winters are quite harsh in the Pešter plateau, because of the mountains which encircle it. One of the climatic features of Serbia is Košava, a cold and very squally southeastern wind which starts in the Carpathian Mountains and follows the Danube northwest through the Iron Gate where it gains a jet effect and continues to Belgrade and can spread as far south as Niš.