DUBROVNIK, a town, port and tourist centre of the southern Croatian coast. It lies at the foot of the limestone Srd Mount (412 m), in a valley enclosed to the south-west by the Lapad plateau and a smaller reef with the oldest part of Dubrovnik. The ancient town core was connected with the suburban zone on the other side of the valley by levelling and filling up of a marshy valley between the Gruz Bay in the north and Stari Porto (Old Port) in the south, as well as by the construction of the Placa (Stradun). Stradun thus became the centre of the town and its main street, connecting two opposite town gates: the Ploce Gate in the east and the Pile Gate in the west. Upon the construction of the port in the Gruz Bay, Gruz was gradually annexed to Dubrovnik and became an integral part of the town. Later on, Dubrovnik extended also to the Lapad peninsula, to lower parts of the Srd slopes and outside the town ramparts toward Zupa. The climate of Dubrovnik is characterized by warm and dry summers and mild winters. The average air temperature in the coldest month (February) is 4.6 °C and in the warmest month (August) 26.2 °C. The cold half of the year accounts for 68 % of the total annual rainfall; the spring accounts for 29, the summer for 14, the autumn for 26 and the winter for 37 rainy days out of the total number of 105 rainy days. Snow occurs extremely rarely; with 2,554 hours of sunshine a year, Dubrovnik ranks among the sunniest towns of southern Europe. In July it has 12.4 hours of sunshine a day, like Alexandria in Egypt. The vegetation is subtropical and extremely luxuriant (olives, almonds, citrus fruit, rosemary, laurel, holm oak, pine, stone pine, cypress). Southeast of the old part of the town is a tourist zone called Ploce (hotels and beaches), west of it is Lapad (sports facilities, hotels, beaches, walking trails), while northwest of it is the Gruz port and Gruz. Economy is based on tourism and seafaring. The town has a number of cultural and educational institutions: the Nautical College, the Tourist College, the University Centre for Postgraduate Studies of the University of Zagreb, the Institute of History of the Croatian Academy of Arts and Sciences, the Dubrovnik Summer Festival and other.