of Serbia is moderate continental with a diversity on local level, caused by geographic location, relief, terrain exposition, presence of river and lake systems, vegetation, urbanization etc. Proximity of the mountain ranges of Alps, Carpathians, Rhodopes, as well as Adriatic Sea and Pannonian plain affect the climate. Location of river ravines and plains in the northern area of the country enable occasional deep southward protrusion of polar air masses on winters, while hot Saharan air often intrudes over the Mediterranean Sea on summers. Average annual air temperature for the period 1961-1990 for the area with the altitude of up to amounts to . The areas with the altitudes of have average annual temperature of around , and over of altitude around . Annual precipitation, generally, rises with altitude. In lower regions, it ranges in the interval from , areas on altitude over receive in average , and some mountainous summits in southwestern Serbia up to . Major part of Serbia has continental precipitation regimen, with peak in the earlier summer period, except for southwest, which receives highest precipitation autumn. May–June is the rainiest month, with the average of 12 to 13% of total annual amount. February and October have the least precipitation. Snow cover can occurs from late November to early March, and majority of days with snow cover is in January. Annual sums of solar radiation are in the interval from 1500 to 2200 hours annually. Surface air circulation is largely influenced by orographic lift. In warmer part of the year, winds from northwest and west prevail. In Vojvodina and Sumadija, east-southeast wind, Košava, dominates over autumn and winter. Southwestern winds prevail in mountainous part of southwestern Serbia. Biodiversity Serbia has five national parks and many national nature reserves encompassing 5% of the territory. National parks Đerdap: (Iron Gate) Tara: Kopaonik: Fruška Gora: Nature parks Stara Planina Golija Kučajske planine Gornje Podunavlje Special nature reservations Deliblato Sands Ludaš Lake Obedska Pond Stari Begej – Carska Bara Nature monuments Đavolja Varoš Human geography Serbia has 6,167 registered settlements: 207 urban and 5,960 rural. See also Geography of Vojvodina Regions of Serbia Geology of Serbia References External links Atlas of Serbia (Wikimedia Commons) geoSerbia, geographic portal of Serbia Institute for the development of water resources "Jaroslav Černi" - Republic of Serbia Water Resources Development Master Plan Danube Facts and Figures: Serbia