LOCATION - The Istrian Region includes a large part of Istria - the largest Adriatic peninsula. The most extreme west point of the Republic of Croatia is in the Istrian Region (Bašanija, promontory Lako) at the 45° of the northern latitude.
Situated in the north-west of the Adriatic Sea, Istria is surrounded by the sea from three sides, while the northern border towards the continent is made up by a line between the Miljski Bay (Muggia) in the direct vicinity of Trieste and the Preluk Bay, right next to Rijeka.
Such favourable geographic position, almost at the heart of Europe, half way between the Equator and the North Pole, Istria has always represented a bridge connecting the Middle European continental area with the Mediterranean.
SURFACE - The Istrian peninsula covers the surface of 3.476 square kilometres. The area is shared by three countries: Croatia, Slovenia, and Italy. A very small part of Istria, merely the northern part of the Miljski peninsula, belongs to the Republic of Italy. Slovenian coastline with the Kopar Bay and a part of the Piran Bay up to the mouth of the Dragonja River is a part of the Republic of Slovenia. The largest part, or 3.130 square kilometres (90% of the surface), belongs to the Republic of Croatia. Most of the Croatian part of the peninsula is situated in the Istrian Region - 2.820 square kilometres, which is 4,98 per cent of the entire surface of the Republic of Croatia. The remaining part belongs to the Primorsko-Goranska Region based on the administrative and territorial subdivision.
CLIMATE - The basic characteristic of the climate of the Istrian peninsula is given by the Mediterranean climate. Along the coast, it gradually changes towards the continent and it passes into continental, due to cold air circulating from the mountains and due to the vicinity of the Alps.
MAIN CHARACTERISTICS - The main characteristics of the Mediterranean climate are dry and warm summers, with the average number if approximately 2.400 sunny hours a year. Winters are mild and pleasant, while it snows very rarely. The annual average of air temperatures along the northern part of the coast is about 14°C, while it is 16°C in the southern area and the islands. January is the coldest month with the average temperature mainly of about 6°C, and July and August are the warmest, with the average temperature of about 24°C. The period when the daytime middle of the air temperature is higher than 10°C approximately lasts for 260 days a year, while hot weather, with a daily maximum above 30°C, lasts for maximally twenty days.
The quantity of rainfall increases from the west coast towards the interior. Characteristic winds are bura, jugo and maestral. Bura blows northwards-southwards and it brings dry and clear skies. The warm wind jugo brings rain, while the mild maestral blows in the summer, from the sea to the continent.
Sea temperature is the lowest in March when it ranges between 9 and 11 °C, while it is the highest in August with 24 °C. Freezing of the coastal border in small and shallow bays is very rare.
WATER FLOWS - Thanks to impermeable flisch layers, Istria does not have scarce water resources. The most significant surface water-flows in the area of the Istrian Region are the Mirna, the Raša, the Boljunčica, the Dragonja Rivers, and the underground Pazinčica. In the water supply sense, there is a significant function of the surface accumulations Butoniga and Boljunčica.
The Mirna River is the longest and the richest Istrian river. Its length is 53 km, it springs near Buzet, and it empties into the Adriatic Sea near Novigrad.
The Raša River is 23 km long, it springs in Čepićko Polje, and it empties into the Raša Bay. The river-basin of the Raša River is very complex - the upper part, also known as Boljunčica, abruptly diverts from Čepićko Polje westwards and it unites with the Raša, continuing through a narrow valley towards the sea. In the continuation of the Boljunčica is a long Plomin Bay, reminding of other canals the Istrian running waters end in.
Similarly to other running waters, the Pazin stream in the first phase flowed towards the Limska Draga, cutting this complex valley - in flisch layers a wider and more open valley-and a narrow canyon through limestone. Along the rift in limestone, the abyss of the Pazinska Cave was opened.
COAST - The length of the Istrian coast, along with islands and islets is 539 kilometres. The west coast of Istria is more indented, and, together with islands, it is 327 kilometres long. East coast, together with islets, is 212 kilometres long.
The majority of the Istrian coast is on the Karst and the limestone grounds. The sinking of Karst recess created specific and branched bays, such as the Pula port, the Medulin bay, the Rovinj coast, the Poreč coast and similar. Isolated limestone heights remained as islands. The coast is well developed with lots of bays, deeper small bays, and river mouths. Except for a series of smaller islets in front of the coast from Poreč to Rovinj, the Brijuni archipelago stands out in the south.
RELIEF - Mild and wavy relief shapes rise up towards the central part of the peninsula, to reach their highest point in the north-east, on the mountain massif of Ćićarija and Učka - peak Vojak with 1396 metres (situated in the Primorsko-Goranska Region).
According to the geological and geomorphic structure, the Istrian peninsula can be divided in three completely different areas. The hilly northern and north-eastern part of the peninsula, due to its scarce vegetation and nude Karst surfaces is also known as White Istria. South-west from White Istria stretches the are this is considerably richer morphologically. These are the lower flisch mountainous tracts consisting of impermeable marl, clay, and sandstone, which is why this part is called Grey Istria. Limestone terrace along the coastline, covered with red earth is called Red Istria.
VEGETATION - One third of the Istrian peninsula is covered with woods. Along the coast and on the islands prevail pine woods and macchia, decorated by trees of holm oak and strawberry-tree.
A special feature of the Istrian vegetation is pedunculate oak next to the Mirna River, characteristically growing in the continental lowlands of Croatia.
The Istrian soil abounds with natural monuments, among which is the especially interesting Brijuni archipelago, which is the habitat of about 680 plant species. It is also decorated by the most diverse vegetation and olive groves. On Učka and Ćićarija, at 500 metres above sea level grows a beech-tree wood.
Among legally protected landscape in the Istrian Region are well-known natural reservations-national park Brijuni, nature park Učka, protected landscape Limski Bay, the Motovunska Wood, park wood Zlatni Rt and orinthologic reservation Palud near Rovinj, park wood Šijana near Pula and the protected landscape Kamenjak in the extreme south of Istria.